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Digitized  by  the  Internet  Archive 

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http://www.archive.org/details/popularchemistryOOstee 


POPULAR 


CHEMISTRY 


J.    DORMAN    STEELE,    Ph.D. 


AUTHOR   OF   A   SERIES   IN   THE   NATURAL   SCIENCES 


NEW  YORK  •:•  CINCINNATI  •:•  CHICAGO 

AMERICAN     BOOK     COMPANY 


Steele's  Science  Se 

:r 

[ES. 

$1.00 

Hygienic  Physiology,      .     .     .     , 

Hygienic  Physiology,  abridged,  . 

•so 

New  Descriptive  Astronomy, 

I.OO 

Popular  Physics, 

1. 00 

Popular  Chemistry, 

1.00 

Popular  Zoology, 

1.20 

Fourteen  Weeks  in  Botany,  .     . 

I.OO 

Fourteen  Weeks  in  Chemistry, 

I.OO 

Fourteen  Weeks  in  Geology, 

I.OO 

Fourteen  Weeks  in  Physics, 

I.OO 

Fourteen  Weeks  in  Philosophy  (o 

Id), 

I.OO 

Fourteen  Weeks  in   Physiology, 

I.OO 

Fourteen  Weeks  in  Zoology,     . 

I.OO 

Manual  of  Science  (New  Key), 

pri 

I.OO 
ce. 

Copies  sent,   postpaid,  on  receipt  of 

Copyright,  1887,  by  A.  S.  Barnes  &  Co. 
Copyright,  1897,  by  American  Book  Company. 


Pop.  Chem. 

J.  J.   L.  &  CO.  4 


THE  GETTY  CENTER 
LIBRARY 


PUBLISHERS'    PREFACE. 


(^INCE  the  publication  of  the  revised  edition 
^ — ^  of  Steele's  "Fourteen  Weeks  in  Chemistry," 
in  1873,  the  study  has  grown  greatly  in  popu- 
larity in  the  schools  of  this  country.  Under  such 
circumstances,  it  has  seemed  advisable  to  enlarge 
somewhat  upon  the  former  treatment  of  the  sub- 
ject ;  and  to  meet  this  change  of  feeling  on  the 
part  of  teachers,  the  present  work  has  been  pro- 
vided. 

The  simplicity  of  statement  and  clearness  of 
method  which  are  the  characteristics  of  Professor 
Steele's  previous  text-books  in  Chemistry,  and  of  all 
his  other  works,  have  been  fully  demonstrated  by 
an  ever-increasing  popular  demand.  No  change  in 
method  of  treatment  has  been  made  in  the  present 
work,  beyond  that  necessitated  by  new  discoveries 
in  this  branch  of  science. 


IV  PUBLISHERS'     PREFACE. 

In  its  new  form,  there  will  be  found  many 
graphic  illustrations,  made  expressly  for  this  edition. 
The  typographical  appearance  of  the  book  has  also 
been  greatly  improved.  We  trust  that  we  have  pre- 
pared a  text-book  that  will  meet  the  wants  of  both 
teachers  and  pupils. 


PREFACE 

TO      THE      FIRST      EDITION 


IN  the  preparation  of  this  httle  volurae  the  author 
lays  no  claim  to  originality :  his  has  been  the  far 
humbler  task  of  endeavoring  to  express,  in  simple, 
interesting  language,  a  few  of  the  principles  and 
practical  applications  of  Chemistry.  There  is  a  large 
class  of  pupils  in  our  schools  who  can  pursue  this 
branch  only  a  single  term,  the  time  assigned  to  it  in 
most  institutions.  The}"  do  not  intend  to  become 
chemists,  nor  even  professional  students.  If  they  wan- 
der through  a  large  text-book,  they  become  confused 
by  the  multiplicity  of  strange  terms,  which  they  can 
not  tarry  to  master,  and,  as  the  result,  too  often  only 
"  see  men  as  trees  walking."  Attempts  have  been 
made  to  reach  this  class  by  omitting  or  disguising 
the  nomenclature  ;  but  this  robs  the  science  of  its 
mathematical  beauty  and  discipline,  while  it  does  not 
fit  the  student  to  read  other  chemical  works  or  to 
understand  their  formulae.  The  author  has  tried  to 
meet  this  want  by  omitting  that  which  is  perfectly 
obvious  to  the  eye — that  which  everybody  knows 
already — that  which  could  not  be  long  retained  in 
the  memory — and  that  which  is  essential  only  to  the 


VI  PREFACE     TO     THE     FIRST     EDITION. 

chemist.  He  has  not  attempted  to  write  a  reference- 
book,  lest  the  untrained  mind  of  the  learner  should 
become  clogged  and  wearied  with  a  multitude  of  de- 
tail He  has  sought  to  make  a  pleasant  study  which 
the  pupil  can  master  in  a  single  term,  so  that  all  its 
truths  may  become  to  him  "  household  words."  Bot- 
any, Natural  Philosophy,  and  Physiology  are  omitted, 
since  they  are  now  pursued  as  separate  branches. 
Unusual  importance  is  given  to  that  practical  part 
of  chemical  knowledge  which  concerns  our  every-day 
life,  in  the  hope  of  bringing  the  school-room,  the 
kitchen,  the  farm,  and  the  shop  in  closer  relationship. 
This  work  is  designed  for  the  instruction  of  youth, 
and  for  their  sake  clearness  and  simplicity  have  been 
preferred  to  recondite  accuracy.  If  to  some  young 
man  or  woman  it  becomes  the  opening  door  to  the 
grander  temple  of  Nature  beyond,  the  author  will  be 
abundantly  repaid  for  all  his  toil. 


PREFACE 

TO      THE      REVISED      EDITION. 


SIX  years  ago,  at  the  solicitation  of  his  fellow- 
teachers,  the  author  offered  this  work  to  the 
profession.  Having  been  prepared  for  the  use  of  his 
own  classes,  and  embodying  his  oral  instructions,  it 
naturally  partook  of  the  peculiarities  of  that  method. 
The  desire  was  to  interest  pupils  in  scientific  study. 
He  believed  that  a  chemical  fact  is  no  less  a  truth 
because  made  attractive  by  an  imaginative  garb.  If 
thus  a  child  could  be  won  to  its  consideration,  the 
intrinsic  beauty  of  the  subject  would  lure  him  on, 
and  so  at  last  he  would  come  to  pursue  it  into  the 
labyrinths  of  dry,  technical  works. 

The  hearty  reception  of  the  book  at  once  and  its 
constantly  increasing  sale,  the  demand  for  an  entire 
series  on  the  same  plan,  words  of  approval  from 
educators  whose  commendation  it  was  a  great  satis- 
faction to  have  won,  the  fact  that  several  other 
series  based  upon  the  same  general  idea  have  since 
appeared,  and,  above  all,  the  assurance  that,  the  books 
have  gone  into  hundreds  of  schools  where  science 
had  never  been  taught  before — have  convinced  the 
author  of  the  inherent  correctness  of  his  view. 


Vlll         PREFACE     TO     THE     REVISED     EDITION. 

A  demand  having  arisen  for  the  admission  of  the 
new  nomenclature  into  the  book,  the  opportunity  is 
gladly  taken  of  making  such  revision  as  the  daily 
use  of  the  work  in  the  class-room,  and  the  advice  of 
others,  have  suggested. 

The  author  would  here  acknowledge  his  special 
indebtedness  to  the  many  teachers  who,  sympathizing 
with  his  plan  of  popularizing  science,  have  pointed 
out  what-  they  considered  defects  in  its  execution, 
and  given  him  the  benefit  of  such  illustrations  and 
methods  as  they  have  found  serviceable.  The  value 
of  these  criticisms  has  been  shown  in  the  increased 
worth  of  each  edition  of  this  series. 

The  usual  authorities  have  been  freely  consulted 
in  this  revision.  The  following  have  been  found  of 
especial  service :  Miller's  Elements  of  Chemistry  (4th 
London  Edition),  Tomlinson's  Miller's  Inorganic  Chem- 
istry, Roscoe's  Lessons  in  Chemistry  (London,  1869), 
Bloxam's  Metals,  and  Fownes'  Manual  of  Chemistrj^ 
(London,  1873).  In  addition,  reference  has  been  had 
to  the  works  of  Cooke,  Draper,  Nichols,  Fresenius, 
Muspratt,  Faraday,  Watts,  Stockhart,  Moffit,  Gmelin, 
Griffin,  Tyndall,  Odling,  Noad,  Williamson,  Wilson, 
Galloway,  Youmans,  Regnault,  Thomson,  Valetin, 
Gregory,  Porter,  Will,  and  many  others. 


SUGGESTIONS  TO  TEACHERS. 


IT  is  advised  that  in  the  use  of  this  book  the  top- 
ical method  of  recitation  should  be  adopted.  So 
fat  as  possible,  the  order  of  the  subjects  is  uniform 
— ^viz.,  Occurrence,  Preparation,  Properties,  Uses, 
and  Compounds.  The  subject  of  each  paragraph  indi- 
cates a  question  which  should  draw  from  the  pupil 
the  substance  of  what  follows.  At  each  recitation 
the  scholar  should  be  prepared  to  explain  any  point 
passed  over  during  the  term,  on  the  mention  of  its 
title  by  the  teacher.  Such  reviews  are  of  incalcu- 
lable value.  While  some  are  reciting,  let  others  write 
upon  specified  topics  at  the  blackboard,  after  which 
the  class  may  criticise  the  thought,  the  language, 
the  spelling,  and  the  punctuation.  Never  allow  a 
pupil  to  recite  a  lesson,  or  answer  a  question,  except 
it  be  a  mere  definition,  in  the  language  of  the  book. 
The  text  is  designed  to  interest  and  instruct  .the 
pupil ;  the  recitation  should  afford  him  an  oppor- 
tunity of  expressing  what  he  has  learned,  in  his 
own  style  and  words.  Every  pupil  should  keep  a 
note-book,  in  which  to  record  under  each  general 
head  of  the  text-book  all  the  experiments,  descrip- 
tions, and  general  information  given  by  the  teacher 
in  class.    In   order  to   accustom   the  scholar  to   the 


X  SUGGESTIONS    TO     TEACHERS. 

nomenclature,  use  the  symbols  constantly  from  the 
beginning ;  they  may  seem  dull  at  first,  but  if  every 
compound  be  thus  named,  a  familiarity  with  chem- 
ical language  will  be  induced  that  will  be  as  pleas- 
ing as  it  will  be  profitable.  If  time  will  admit,  in 
addition,  have  weekly  essays  prepared  by  the  class, 
combining  information  from  every  attainable  source. 

Ocular  demonstration  is  absolutely  necessary  to 
any  progress  in  the  study  of  chemistry.  Simple 
directions  with  regard  to  the  experiments  are  gi"\4pn 
in  the  Appendix  (see  page  261)  which  will  enable 
the  unprofessional  chemist  to  perform  them  readily, 
and,  in  case  it  is  convenient  for  the  pupils  to  work 
in  the  laboratory,  will  guide  them  in  their  investi- 
gations. The  subject  of  Qualitative  Analysis  is  also 
explained  so  clearly,  and  the  directions  are  so  com- 
plete (see  page  288),  that  even  the  amateur  student 
can  grasp  the  subject  and  demonstrate  its  principles. 

Teachers  desiring  pleasant  information  to  relieve 
the  recitation  hour,  will  find  it  in  that  delightful 
work  of  Dr.  Nichols,  Fireside  Science.  Many  curious 
and  entertaining  stories  and  facts  are  given  in  a 
book  entitled  Treasures  of  the  Earth.  For  common 
works  of  reference,  Roscoe  &  Schorlemmer's  Treatise 
on  Chemistry,  6  vols,  octavo,  or  Miller's  Elements  of 
Chemistry,  3  vols,  octavo,  will  be  most  generally 
useful. 


TABLE   OF  CONTENTS. 


I.— I  NTRODUCTION. 

PAGE 

DBFUnTIONS 

CONSTITUTION  OF  BODIES ^ 

NOTATION  AND  NOMENCLATURE • 5 

CLASSIFICATION  OF  ELEMENTS 6 

ORGANIC  AND  INORGANIC   CHEMISTRY 7 

II.-INORGANIC     CHEMISTRY. 

1.— THE  NON-METALS. 

Oxygen,  Ozone 

"Weighing  and  Measuring  Gases 

Nitrogen,  Nitric  Acid,  Nitrous  Oxide,  etc 27 

Hydrogen,  Water,  etc 

Carbon,  Carlon  Dioxide,  CoaUGas,  etc 53 

75 
Combustion 

The  Atmosphere 

The  Halogens,    Chlorine,  Hydrochlorie  Acid,  Acids, 

Bases,  Salts,  Bromine,  Iodine,  Fluorine 92 

Sulphur,  Sulphuric  Acid,  etc 10^ 

Valence 

Phosphorus,  Matches,  etc 

117 
Arsenic 

Boron 1^0 

122 
Silicon,  Glass,  etc 


Xll  TABLE     OF     CONTENTS. 

2.— THE  METALS.  page 

Potassium 127 

Sodium 131 

Ammonium 136 

Calcium 138 

Strontium  and  Barium 143 

Magnesium 144 

Aluminium,  Clay 145 

Spectrum  Analysis 147 

Iron,  Steel,  Bessemer' s  x>'>'ocess,  etc 150 

Zinc ^ 158 

Tin 160 

Copper 161 

Lead 162 

Gold 165 

Silver,  Photography,  etc 167 

Platinum 173 

Mercury,  Mirrors,  etc 174 

The  Alloys 176 

Review  of  the  Properties  of  the  Metals    179 

III.— ORGANIC    CHEMISTRY. 

INTRODUCTION 185 

The  Paraffines  and  their  Derivatives 189 

The  Alcohols 193 

Fermentation,  Beer,  Wine,  etc 195 

Aldehydes  and  Acids,   Vinegar,  Acetic  Acid,  Oxalic 

Acid,  etc 200 

Ethers   and  Ethereal   Salts,  Fats,   Glycerin,   Soap, 

etc 204 


TABLE     OF     CONTENTS.  XIU 

PAGE 

Halogen  Derivatives,  Chloroform,  Chloral,  etc 209 

The  Carbohydrates,  Starch,  Cellulose,  Sugar 211 

Aromatic  Compounds,  Benzene,  Aniline,  etc 221 

Terpenes  and  Camphors,  Essential   Oils,   Resins,  Bal- 
sams, Rubber 225 

Alkaloids,  Morphine,  Quinine,  Nicotine,  Strychnine, 

etc 231 

Dyes  and  Dyeing,  Tanning,  etc 235 

Albuminous  Bodies 239 

Domestic  Chemistry 243 

CONCLUSION,  Chemistry  of  the  Sunbeam,  etc 249 

IV.  — APPENDIX. 

Table  of  the  Elements 257 

Names  and  Formulas  of  the  more  Important  Chemicals  . . .  258 

Directions  for  Experiments 261 

Qualitative  Analysis 288 

Questions  for  Class  Use 304 

Index 321 

Glossary 325 


I. 

Introduction, 


"  I  SYMPATHIZE  with  that  beautiful  idea  of  Oersted,  which  he  expressed 
in  the  now  familiar  phrase,  '  The  laws  of  Nature  are  the  thmights  of  God.'' 
*  *  *  Through  the  great  revolutions  which  have  taken  place  in  the 
forms  of  thought,  the  elements  of  truth  in  the  successive  systems  have 
heen  preserved,  while  the  error  has  been  as  constantly  eliminated ;  and  so, 
as  I  believe,  it  always  will  be,  until  the  last  generalization  of  all  brings  us 
into  the  presence  of  that  law  which  is  indeed  the  thought  of  G-od." 

J.  P.  CooKE,  Jb. 


AVOGADRO'S    LAW. 

"  Equal  volwmes  of  all  substances,  when  in  a  state 
of  gas,  and  under  like  conditions,  contain  the  same 
number  of  molecules^    See  Physics,  p.  23. 


THE 

ELEMENTS  OF  CHEMISTRY 


INTRODUCTION. 

Chemistry  treats  of  the  composition  of  substances, 
and  all  changes  in  composition  which  may  take  place. 

All  the  changes,  or  phenomena,  which  matter 
exhibits,  may  be  divided  into  two  groups:  1st.  Those 
in  which  the  composition  is  not  altered.  2d.  Those 
in  which  a  change  in  composition  takes  place.  The 
first  are  physical  phenomena,  the  second  are  chemical 
phenomena. 

Uxamples :  1st.  Fall  of  a  stone,  vibration  of  a 
tuning-fork,  and  all  phenomena  of  motion ;  boiling  of 
water,  magnetizing  of  iron.  2d.  Rusting  of  iron, 
souring  of  milk,  burning  of  candle. 

No  destruction  of  matter  is  possible.  When  a 
substance  disappears,  as  in  the  boiling  of  water  or 
the  burning  of  a  candle,  this  is  because  it  is  changed 
into  an  invisible  form  (gas),  and  not  because  it  has 
been  destroyed.  In  its  new  form  it  still  has  the 
properties  of  lueight  and  impenetrability,  which  prove 
it  to  be  matter. 

An  JElement  is  a  kind  of  matter  which  has  never 
been    separated   into    other    substances. — Examples : 

I 


2  ELEMENTS     OF     CHEMISTKY. 

gold,  sulphur.  The  number  of  elements  now  known 
is  about  seventy.*  The  larger  number  of  these  are 
rare.  A  few  of  the  elements  occur  naturally,  but 
most  substances  are  composed  of  two  or  more  ele- 
ments, and  are  therefore  called  compounds. 

Compounds,  in  their  properties,  are  in  general 
very  unlike  their  elements. f — Examples:  yellow  sul- 
phur and  white  quicksilver  form  red  vermilion  ;  inert 
charcoal,  hydrogen,  and  nitrogen  produce  the  deadly 
prussic  acid ;  solid  charcoal  and  sulphur  make  a 
colorless  liquid ;  poisonous  and  offensive  chlorine 
combines  with  the  brilliant  metal  sodium  to  form 
common  salt. 

Chemical  Affinity,  or  Chemism,  is  the  name  given 
to  that  power  which  causes  the  chemical  union  of 
substances,  and  which  holds  the  elements  together 
in  compounds.  It  acts  only  at  insensible  distances, 
and  generally  with  great  energy.^  If  chemism  should 
suddenly  cease,  not  only  would  all  chemical  action 
be  impossible,  but  almost  all  substances  would  at 
once  change  their  character ;  for  all  compounds 
would  be  resolved  into  their  elements : — all  water 
would  disappear  into  two  invisible  gases,  the  solid 
rocks    would    fall    to    powder,    and    all    animal    and 


*  It  is  not  probable  that  the  list  is  complete,  but  we  can  not  suppose 
that  any  very  abundant  element  is  yet  to  be  found. 

t  "The  elements  have  no  more  likeness  to  the  compounds  which  they 
form  than  the  separate  letters  of  the  alphabet  have  to  the  words  which 
may  bo  made  from  them."— Miller. 

t  Nothing  in  the  nature  or  appearance  of  an  element  indicates  its 
chemical  affinity,  and  it  is  only  by  trial  that  we  caf\  tell  with  what  it  will 
combine.  This  attraction  is  not  a  mere  freak  of  nature,  but  is  imparted  to 
matter  by  Qod  Himself. 


INTRODUCTION.  3 

vegetable   substances   would   be   changed   into   three 
gases  and  a  substance  like  charcoal. 

Heat  and  Light  favor  chemical  action,  and  fre- 
quently develop  an  affinity  where  it  seems  to  be 
wanting.  The  former,  especially,  tends  to  drive  the 
elements  of  a  compound  without  the  range  of  old 
attractions  and  within  that  of  new  ones.  Electricity 
is  also  a  powerful  agent  in  producing  chemical  ac- 
tion.— Examples :  gun-cotton,  when  lying  in  the  air, 
is  apparently  harmless,  but  a  spark  of  fire  will  pro- 
duce a  brilliant  flash,  and  cause  it  to  disappear  as  a 
gas  ;  nitrate  of  silver  in  contact  with  organic  matter 
turns  black,  by  the  action  of  the  light ;  an  electric 
current  led  through  acidulated  water  decomposes  it 
into  its  constituent  gases. 

Solution  aids  in  chemical  change,  as  it  permits 
the  particles  of  substances  to  come  within  the  range 
at  which  chemism  can  act. — Example :  sodium  car- 
l)onate*  and  tartaric  acid  mixed  in  a  glass  will  not 
combine,  but  the  addition  of  water  will  cause  a 
violent  effervescence. 

Law  of  Definite  Proportions. — Chemical  combina- 
tion always  takes  place  between  definite  weights  of 
substances. 

Law  of  Multiple  Proportions. — If  two  elements, 
A  and  B,  combine  in  different  proportions,  the  relative 
quantities  of  B  which  combine  with  any  fixed  quan- 
tity of  A  bear  a  simple  ratio  to  one  another. 
/  Constitution  of  Bodies. — The  phenomena  of  both 
Physics  and   Chemistry  lead  to  the   conclusion  that 

♦  Carbonate  of  Soda, 


4  ELEMENTS    OF     CHEMISTRY. 

all  bodies  are  made  up  of  minute  particles  which 
are  never  in  actual  contact  with  each  other,  and  are 
always  in  motion.  In  any  given  substance,  all  the 
constituent  particles  are  alike  and  of  the  same  com- 
position as  the  substance.  These  particles  are  called 
molecules.  A  molecule  is  the  smallest  particle  of  a 
substance  ivhich  can  exist  in  the  free  state.  A  phys- 
ical change  goes  no  further  than  the  molecule,  and 
hence  does  not  affect  the  nature  of  the  substance ; 
but  a  chemical  change  is  a  change  of  substance,  and 
hence  must  consist  in  the  breaking  up  of  molecules 
and  the  formation  of  new  ones.  This  is  explained 
by  the  assumption  that  the  molecules  are  compound, 
each  molecule  being  composed  of  still  smaller  parti- 
cles. These  smaller  particles  are  called  atom,s,  and 
may  be  defined  as  the  indivisible  constituents  of  mole- 
cules. They  are  the  smallest  particles  of  elements 
which  can  take  part  in  chemical  changes.  Thus  a 
molecule  consists  of  atoms  held  together  by  chemism. 
In  an  element,  the  molecules  are  made  up  of  atoms 
of  the  same  kind ;  in  a  compound,  the  molecules 
consist  of  atoms  of  different  kinds. 

Atoms  differ  from  each  other  in  chemism,  in 
weight,  and  in  valence. 

The  Atomic  Weight  of  an  element  expresses  the 
weight  of  its  atom  compared  with  that  of  the  atom 
of  hydrogen. 

Molecular  Weight  is  the  sum  of  the  weights  of 
the  atoms  in  the  molecule. 

Valence*  is  the  property  of  an  atom  by  virtue  of 

♦  The  property  of  valence  is  treated  on  page  111. 


INTRODUCTION.  0 

which  it  can  hold  a  definite  number  of  other  atoms 
in  combination. 

Chemical  Notation.  —  For  the  sake  of  brevity-j 
ohemists  use  a  kind  of  short-hand.  An  atom  is 
represented  by  the  first  letter  of  its  English  name. 
When  that  would  produce  confusion,  the  Latin  initial 
is  substituted,  and  in  some  cases  a  second  letter 
added. — Examples :  carbon  and  chlorine  both  com- 
mence with  C  ;  so  the  latter  takes  CI  for  its  symbol. 
Silver  and  silicon  both  begin  with  Si,  hence  the 
former  assumes  Ag,  from  its  Latin  name,  Argentum. 
If  more  than  one  atom  of  an  element  is  contained 
in  a  molecule  of  a  compound,  this  is  shown  by 
writing  the  number  below  the  symbol. — ExciTuple : 
H2O  indicates  that  in  a  molecule  of  water  there  are 
two  atoms  of  hydrogen  and  one  of  oxygen. 

Molecules  are  represented  by  grouping  together 
the  symbols  of  their  constituent  atoms.  Such  a 
group  of  symbols  is  called  the  formula  of  the  mole- 
cule or  substance. 

Chemical  action  or  "  reaction  "  between  substances 
is  expressed  b}^  means  of  chemical  equations  which 
resemble  those  of  algebra,  and  whose  terms  are  mo- 
lecular formulas. — Exam,ple  :  NaCl  +  AgN03=:  NaN03  + 
AgCl.  The  sign  +  indicates  mixture ;  the  sign  = , 
conversion  into. 

L  Nomenclature. — The  elements  which  were  known 
anciently  retain  their  former  names.  Those  discov- 
ered more  recently  are  named  from  some  peculiar- 
ity.— Examples :  chlorine,  from  its  green  color  ;  bro- 
mine,  from   its  bad  odor.     The  uniform   termination 


6  ELEMENTS     OF     CHEMISTRY. 

ium  has  been  given  to  the  lately  found  metals. — 
Examples :  potassium,  sodium.  A  similarity  of  end- 
ing in  non-metallic  elements  indicates  some  analogy. 
— Examples :  silicon,  boron  ;   iodine,  bromine. 

Compounds  are  named  from  their  constituent 
atoms.  When  a  compound  contains  only  two  ele- 
ments (a  binary  compound),  the  names  of  the  two 
are  placed  together  and  one  (the  non-metal)  takes  the 
termination  ide.  Thus,  potassium  and  iodine  form 
the  compound  which  is  written  KI,  and  read  potas- 
sium iodide ;  sodium  and  chlorine,  NaCl,  sodium 
chloride ;   zinc  and  oxygen,  ZnO,  zinc  oxide. 

Other  rules  for  nomenclature  will  be  noticed  as 
occasion  demands. 

Classification  of  the  Elements. — The  elements  are 
usually  divided  into  two  classes  :  Metals  and  Notv- 
Tnetals.  The  metals,  as  a  class,  are  electro-positive  * 
with  reference  to  the  non-metals,  or  what  amounts 
to  the  same  thing,  the  non-metals  are  electro-nega- 
tive* in  their  behavior  toward  the  metals.  The 
metals  are  the  basef-forming  elements,  the  non- 
metals  the  acid  f-f orming  elements.  These  classes, 
however,  are  not  separated  by  any  sharply  defined 
difference  in  properties,  but  one  shades  gradually 
into  the  other : — all  the  elements  may  be  arranged 
in  a  series  in  such  a  way  that  each  is  electro-posi- 
tive toward  all  which  follow  it,  and  electro-negative 
toward   all  which   precede   it;  and  certain  elements 


♦  See  definition  of  these  terms  under  Electricity  in  Steele's  "Popular 
Physics. " 

t  See  explanation  of  these  terms  on  pages  98  and  09. 


INTRODUCTION.  7 

are  found  to  form  both  acids  and  bases.  Thus  the 
division  is  a  somewhat  arbitrary  one,  and  is  retained 
chiefly  for  convenience  of  study. 

Organic  and  Inorganic  Chemistry. — The  division 
of  Chemistry  into  organic  and  inorganic  Chemistry 
is  still  kept,  though  the  significance  of  the  names 
has  changed.  It  was  formerly  thought  that  "  organic  " 
substances  could  be  produced  only  by  the  agency 
of  plant  or  -animal  life,  and  thus  formed  a  group 
quite  distinct  from  the  ''inorganic"  or  mineral  sub- 
stances. But  it  has  been  found  that  many  "  organic  " 
substances  can  be  made  in  the  laboratory  from 
"  inorganic "  substances  without  the  aid  of  the  vital 
process.  The  organic  substances  always  contain  car- 
bon, and  include  most  of  the  compounds  into  which 
this  element  enters,  so  that  organic  Chemistry  is 
now  defined  as  the  Chemistry  of  the  Compounds  of 
Carbon,  while  inorganic  Chemistry  deals  with  the 
compounds  of  the  other  elements.   -^ 


II. 

Inorganic  Chemistry. 


"In  the  de-oxidation  and  re-oxidation  of  the  hydrogen  in  a  single  drop 
of  water,  we  have  before  us,  so  far  as  force  is  concerned,  an  epitome  of 
the  whole  of  Ufe."— Hinton. 


INORGANIC  CHEMISTRY. 


THE     NON-METALS. 
OXYGEN. 

Symbol,  0 Atomic  Weight,  16 Specific  Gravity,  1.1. 

The  name  Oxygen  means  acid-former,  and  was 
given  because  it  was  supposed  to  be  the  essential 
principle  of  all  acids. 

Occurrence. — 0  is  the  most  abundant  of  all  the 
elements — comprising  by  weight  f  of  the  water,  f  of 
all  animal  bodies,  about  i  of  the  crust  of  the  earth, 
and  more  than  ^  of  the  air. 

Preparation. — Although  0  is  present  in  the  air  in 
large  quantities,  it  can  not  be  readily  obtained  from 
this  source,  but  is  usually  prepared  from  one  of  its 
compounds  by  heat.  Thus,  if  oxide  of  mercury  is 
heated,  it  yields  0  and  mercury.  We  may  represent 
the  chemical  change  which  takes  place  by  a  chem- 
ical equation : 

HgO  =  Hg  +  0  ; 

which  is  read,  oxide  of  mercury  is  converted  into, 
or  gives,  mercury  and  oxygen.  The  equation  ex- 
presses more  than  the  mere  fact  that  this  change 
has  taken  place ;  for  each  atomic  symbol  stands  for 


12  INORGANIC     CHEMISTRY. 

a  definite  weight  of  the  element  which  it  represents, 
and  the  equation  consequently  means,  216  parts  of 
oxide  of  mercury  give  2  00  parts  of  mercury  and 
16  parts  of  oxygen. 

Another  substance  which  yields  0'  readily  when 
heated  is  potassium  chlorate  (KCIO3).  The  best 
method  of  preparing  0  for  experimental  purposes  is 
to  heat  a  mixture  of  equal  parts  of  this  substance 
and  manganese  dioxide  (Mn02).*  The  manganese 
dioxide  remains  unchanged,  but  in  some  way  which 
is  not  understood,  causes  the  potassium  chlorate  to 
give  off  its  0  at  a  lower  temperature  and  more 
regularly  than  when  it  is  heated  alone.  The  mixed 
substances  are  heated  in  a  flask  and  the  gas  collected 
over  water  in  a  pneumatic  trough,  as  shown  in  the 
illustration. 

The  reaction  may  be  represented  thus : 

KCIO3       =        KCl      +      30 
39  +  35.5  +  48  39  +  35.5  3x16 


122.5  74.5  48 


122.5 

The  0  obtained  will  be  tUts  of  the  potassium 
chlorate  used,  i.e.,  every  122.5  parts  by  weight 
(grs.,  oz.,  or  lbs.)  will  yield  48  parts  (grs.,  oz.,  or  lbs.) 
of  0,  and  74.5  parts  (grs.,  oz.,  or  lbs.)  of  KCl. 

Properties. — 0  has  no  odor,  color,  or  taste.  It  is 
but  very  slightly  soluble  in  water.    It  combines  with 

•  This  substance  is  sometimes  known  as  binoxide  of  manganese,  and, 
because  of  its  color,  as  the  black  oxide  of  manganese. 


13 


Collecting  O  over  water. 


every  element  except  fluorine,  helium,  and  argon. 
From  some  of  its  compounds  it  escapes  explosively 
on  the  slightest  blow,  while  from  others  it  can  be 
liberated  only  by  the  most  powerful  means.  Its 
action  on  a  substance  is  called  oxidation  of  the  sub- 
stance, and  the  products  are  oxides.  It  is  incombusti- 
ble, but  a  vigorous  supporter  of  combustion. 

The  following  experiments  will  illustrate  its  chem- 
ical energy. 

1.  By  blowing  quickly  upward  upon  a  candle,  ex- 
tinguish the  flame,  and  leave  a  glowing  wick.  If 
this  be  plunged  into  a  jar  of  0,  the  coal  will  burst 
into  a  brilliant  blaze.  The  experiment  may  be 
repeated  many  times  before  the  0  will  be  exhausted. 


14 


INORGANIC     CHEMISTRY. 


Fig.  2. 


Sulplmr  in  O. 


Fig.  3. 


A  new  colorless  gas,  COj,  called  carbon  dioxide  ("car- 
bonic acid")  is  formed  by  the  combustion. 

2,  Ignite  a  bit  of  sulphur 
placed  in  a  "deflagrating  spoon  " 
(see  Appendix,  p.  264),  and 
lower  it  into  a  jar  of  0.  It  will 
burn  with  a  beautiful  blue  light, 
and  the  formation  of  sulphur 
dioxide,  SO2  ("sulphurous  acid"), 
which  has  the  pungent  odor  of 
a  burning  sulphur  match. 

3.  Straighten  one  end  of  a 
watch-spring  and  fasten  it  in  a  bit  of  thin  board ; 
heat  the  other  end  slightly  and  dip  it  into  powdered 

sulphur.  Light  this  and  plunge 
it  into  a  jar  of  0,  closing  the 
mouth  of  the  jar  with  the  board. 
The  burning  sulphur  will  ig- 
nite the  steel,  which  will  burn 
without  flame  with  a  shower 
of  fiery  stars,  while  melted  glob- 
ules of  the  oxide  of  iro^i  yre^^O^ 
will  fall  upon  the  bottom  of 
the  jar. 

4.  Place  in  the  bottom  of  a  deflagrating  spoon  a 
little  fine,  dry  chalk ;  then  wipe  a  bit  of  phosphorus, 
about  the  size  of  a  pea,  very  carefully  and  quickly 
between  pieces  of  blotting-paper ;  lay  this  upon  the 
chalk,  and,  holding  the  spoon  over  a  large  jar  of  0, 
ignite  the  phosphorus  with  a  heated  wire,  and  lower 
it  steadily  into   the  gas.    The  phosphorus  will  burst 


A  watch-spring  in  O. 


OXYGEN, 


15 


Phosphorus  ill  O.     "  The  })ho8phoric  sun.''' 


into  a  flood  of  blinding  light,  while   dense  fumes  of 
phosphorus     pentoxide, 
P2O5,  will  roll  down  the 
sides  of  the  jar. 

5.  Make  a  little  tas- 
sel of  zinc-foil,  tip  the 
ends  with  sulphur  as 
in  the  3d  experiment, 
ignite  and  lower  into  a 
jar  of  0.  It  will  burn 
with  a  dazzling  light, 
forming  zinc  oxide 
(ZnO). 

6,  If  a  piece  of  char- 
coal-bark be  ignited  and 

lowered  into  a  jar  of  0,  it  will  deflagrate  with  bright 
scintillations. 

Oxygen  the  Active  Agent  of  the  Air. — The  burn- 
ing of  substances  in  air  resembles  the  burning  in  0, 
except  that  it  is  never  so  energetic.  It  is,  indeed,  a 
true  oxidation,  and  the  oxides  formed  are  the  same 
as  those  produced  in  the  0  we  prepare.  The  burn- 
ing candle  gives  off  CO 2,  sulphur  SO 2,  phosphorus 
PaOg,  the  glowing  iron  which  the  blacksmith  draws 
from  his  forge  forms  scales  of  Fe304,  which  fly 
blazing  in  every  direction  under  the  blows  of  his 
hammer.*  Comprising  about  one  fifth  of  the  com- 
mon air,  0  is  ever-present,  ever-waiting. 

*  Quite  in  contrast  to  this  pyrotechnic  display  is  the  action  of  the  O 
upon  the  Fe  contained  in  writing-fluid.  At  first  the  words  are  pale  and 
indistinct,  but  in  a  few  hours  the  O,  noiselessly  combining  with  the  metal 
(see  p.  17),  brings  out  every  letter  in  clear,  bold  characters  upon  the  page. 


16  INORGANIC     CHEMISTRY. 

We  open  the  damper  of  the  stove  and  the  air 
rushes  in.  The  0  immediately  attacks  the  heated 
fuel.  Every  two  atoms  combine  with  an  atom  of  C 
and  liy  off  into  the  air  as  CO  2. 

The  water  of  a  river  becomes  foul  from  the  dis- 
charge of  drains  and  sewers.  As  it  flows  along,  ex- 
posed to  the  air,  the  0  dissolves  in  it,  attacks  each 
particle  of  organic  impurity  and  slowly  burns  it  up  ; 
thus  rendering  the  river-water  once  more  fit  for  use. 

We  wipe  our  knives  and  forks,  and  lay  them 
carefully  away ;  but  if  we  have  left  on  them  a  par- 
ticle of  moisture,  since  H2O  favors  chemical  change, 
the  0  will  find  it,  and  corrode  the  steel.* 

An  animal  dies,  and  the  0  is  an  important  agent  in 
removing  its  body.  The  molecules  which  have  been 
used  to  perform  the  functions  of  life,  are  broken  up  by 
the  0,  and  their  atoms  enter  into  new  combinations. 

0  in  the  Human  System. — We  take  the  air  into 
our  hmgs.  Here  the  blood  f  absorbs  the  0,  and  bears 
it  to  all  parts  of  the  body,  depositing  it  wherever 
it  is  needed.  Laden  with  this  life-giving  element, 
the  vital  fluid  sweeps  tingling  through  every  artery 
to  the  remotest  capillary  tubes,  sends  the  quick 
flush  to  the  cheek,   combines  with  a  portion  of  the 


*  The  compound  here  formed  will  be  a  higher  oxide  than  that  produced 
at  the  blacksmith's  forge,  since  a  portion  of  the  O  was  there  prevented  from 
uniting  with  the  iron  by  the  heat.  It  will  be  the  red  oxide  of  iron  (PejO,, 
ferric  oxide),  or  common  iron  rust,  as  we  see  it  on  stoves  and  other  utensils. 

+  "The  blood  is  full  of  red  corpuscles  or  cells  containing  Fe.  These  arc 
so  tiny,  that  a  million  of  them  cluster  in  the  drop  which  will  cling  to  the 
point  of  a  needle.  Quickly  a.ssuming  a  tawny  hue,  like  the  decayed  leaves 
of  autumn,  they  change  so  i-apidly  that  30,000,000  perish  with  every  breath." 
—Draper. 


OXYGEN.  17 

food  thrown  into  the  circulation  from  the  stomach, 
breaks  up  every  worn-out  tissue,  burns  up  the  mus- 
cles as  they  do  their  work,  until  at  last  it  comes 
back  through  the  veins  dark  and  thick  with  the 
products  of  the  combustion — the  cinders  of  the  flame- 
less  fire  within  us. 

Combustion  and  Heat. — All  ordinary  processes  of 
decay  and  fire,  are  produced  by  the  action  of  0  on  sub- 
stances, and  are  different  forms  of  oxidation.  They 
differ  only  in  the  time  employed  in  the  operation. 
If  0  unites  rapidly,  we  call  it  fire  ;  if  slowly,  decay. 
Yet  the  process  and  the  products  are  the  same.  A 
stick  of  wood  is  burned  in  the  stove,  and  another 
rots  in  the  forest,  but  the  chemical  change  is  iden- 
tical. In  the  oxidation  of  an  atom  of  C,  a  certain 
amount  of  heat  is  produced.  Hence,  the  house  that 
decays  in  fifty  years,  gives  out  as  much  heat  during 
that  time  as  if  it  had  been  swept  off  by  a  fierce  con- 
flagration in  as  many  minutes. 

Tlie  Igniting  Point  of  any  substance  is  the  tem- 
perature at  which  "it  catches  fire."  We  elevate  the 
heat  of  a  small  portion  to  the  point  of  rapid  union 
with  0,  and  that  part  in  burning^  will  give  off  heat 
enough  to  support  the  combustion  of  the  rest. — 
Example :  In  making  a  fire,  we  take  paper  or  shav- 
ings, which,  being  poor  conductors  of  heat,  and  ex- 
posing a  large  surface  to  the  action  of  0,  are  easily 
raised  to  the  required  temperature.  Having  thus 
obtained  sufficient  heat  to  start  the  combustion  of 
chips  or  pine  sticks,  we  gradually  increase  it  until 
there  is  enough  to  ignite  the  coal  or  wood. 


18  INORGANIC     CHEMISTRY. 

Extinguishing'  Fires. — Blowing  on  a  candle  or 
lamp  extinguishes  it,  because  it  lowers  the  heat  of 
the  flame  below  the  igniting  x^oint  of  the  gases. 
Fires  are  put  out  by  water  partly  for  the  same  reason, 
and  also  because  it  envelops  the  wood  and  shuts  off 
the  air.  If  a  person's  clothes  take  fire,  the  best 
course  is  to  wrap  him  in  a  blanket,  carpet,  coat,  or 
even  in  his  own  garments.  This  smothers  the  fire 
by  shutting  out  the  0.  Great  care  should  be  taken  in 
a  fire  not  to  open  the  doors  or  windows,  so  as  to  cause 
a  draught  of  air.  The  entire  building  may  burst 
into  a  blaze,  when  the  fire  might  have  languished 
for  want  of  0,  and  so  have  been  easily  extinguished. 

Spontaneous  Combustion. — Sometimes  substances 
absorb  oxygen  from  the  air  so  rapidly,  that  heat 
enough  is  evolved  to  cause  ignition  ;  or  if  the  sul)- 
stances  are  incombustible,  other  bodies  in  contact 
with  them  may  be  kindled. 

The  waste  cotton  used  in  mills  for  wiping  oil  from 
the  machinery,  when  thrown  into  large  heaps,  often 
absorbs  0  from  the  air  so  rapidly  that  it  bursts  into 
a  blaze.  Fires  are  often  started  in  this  way,  both  in 
manufactories  and  on  board  ship.  Similar  cases  of 
spontaneous  combustion  occur  in  hay-ricks  in  which 
the  hay  has  been  put  up  damp. 

Heaps  of  coal  take  fire  from  the  oxidation  of  the 
iron  pyrites  contained  in  them.  This  is  favored  by 
the  moisture  of  the  air. 

All  supposed  instances  of  spontaneous  combustion 
in  the  human  body  have  been  proved  to  be  mistakes 
or  deceptions. 


OXYGEN.  ly 

^/ 
The  Human  Furnace. — The  body   is  like  a  stove 

in  which  fuel  is  burned,  and  the  chemical  action  re- 
sembles that  in  any  other  stove.  This  combustion  pro- 
duces heat,  and  our  bodies  are  kept  warm  by  the 
constant  fire  within  us.  We  thus  see  why  we  fortify 
ourselves  against  a  cold  day  by  a  full  meal.  When 
there  is  plenty  of  fuel  in  our  human  furnaces,  the 
0  burns  that ;  but  if  there  is  a  deficiency,  the  de- 
structive 0  must  still  unite  with  something,  and 
so  it  combines  with  the  flesh  ; — first  the  fat,  and  the 
man  grows  poor ;  then  the  muscles,  and  he  grows 
weak ;  finally  the  brain,  and  he  becomes  crazed. 
He  has  burned  up,  as  a  candle  burns  out  to  dark- 
ness. 

0  Produces  Motion. — Ah  soon  as  we  begin  to  per- 
form any  unusual  exercise,  we  commence  breathing 
more  rapidly,  showing  that,  in  order  to  do  the  work, 
we  need  more  0  to  unite  with  the  food*  and  mus- 
cles. In  very  violent  labor,  as  in  running,  we  are 
compelled  to  open  our  mouths,  and  take  deep  inspi- 
rations of  0.  This  increased  fire  within  elevates  the 
temperature  of  the  bo<ly,  and  we  say  "we  are  so 
warm  that  we  pant."  Really  it  is  the  reverse.  The 
panting  is  the  cause  of  our  warmth. 

During  sleep  the  organs  of  the  body  are  mostly 
at  rest,  except  the  heart.  To  produce  this  small 
muscular  exertion  very  little  0  is  required.  As  our 
respiration  is,  tnerefore,   slight,   our  pulse  sinks,  the 

*  It  is  probable  that  a  portion  of  our  food,  especially  the  carbonaceous, 
is  oxidized  directly  without  becoming  an  integral  part  of  the  body;  but 
oxidation  takes  place  in  the  tissues  of  all  parts  of  the  body,  the  oxygen 
being  carried  by  the  red-blood  corpuscles. 


20  INORGANIC     CHEMISTRY. 

heat  of  our  body  falls,  and  we  need  much  additional 
clothing  to  keep  warm.*  Thus  we  require  0  not 
only  to  keep  us  warm,  but  also  to  do  all  our  work. 
Cut  off  its  supply,  and  we  grow  cold  ;  the  heart 
struggles  spasmodically  for  an  instant,  but  the  mo- 
tive power  is  gone,  and  we  soon  die. 

How  0  Gives  us  Strength. — Our  muscles,  as  well 
as  the  food  from  which  they  are  formed,  consist  of 
complex  organic  bodies,  and  the  pent-up  energy  is 
very  great.  Thus  in  flesh,  starch,  sugar,  etc.,  the 
molecules  are  very  complex  (see  p.  188),  and  when 
these  oxidize  into  the  simpler  ones  of  water,  carbonic 
acid,  and  ammonia,  the  potential  energy  is  trans- 
formed into  heat  and  muscular  strength.f  As  no  mat- 
ter is  either  lost  or  gained  in  any  chemical  change, 
so  also  no  energy  is  lost  or  gained,  but  all  must 
be  accounted  for. 

The  Burning  of  the  Body  by  0. — A  man  weighing 
150  lbs.  has  64  lbs.  of  muscle.  This  will  be  burned 
in  about  80  days  of  ordinary  labor.  As  the  heart 
works  day  and  night,  it  burns  out  in  about  a  month. 
So  that  we  have  a  literal  "new  heart"  eveiy  thirty 
days.  We  thus  dissolve,  melt  away  in  tinu',  and 
only   the    shadow   of   our   bodies   can    be    called    our 

*  Animals  that  hibernate  show  the  same  truth.  The  marmot,  for 
instance,  in  summer  is  warm-blooded;  in  the  winter  its  pulse  sinks  from 
140  to  4,  and  its  heat  corresponds.  The  bear  goes  to  his  cave  in  the  fall, 
fat ;  in  the  spring  he  comes  out  lean  and  lank.  Cold-blooded  animals  have 
very  inferior  breathing  apparatus.  A  frog,  for  example,  has  to  swallow  air 
by  mouthfuls,  as  we  do  water.  Others  have  no  lungs  at  all,  and  breathe 
in  a  little  air  through  the  skin,  enough  barely  to  exist.  Is  it  strange  tliey 
are  cold-blooded? 

t  See  discussion  of  energy  and  the  transformation  of  potential  into 
kinetic  energy  in  "Steele's  Popular  Physics." 


OXYGEN.  21 

own.  They  are  like  the  flame  of  a  lamp,  which 
appears  for  a  long  time  the  same,  since  it  is  "cease- 
lessly fed  as  it  ceaselessly  melts  away."  The  rapidity 
of  this  change  in  our  bodies  is  remarkable.  Says 
Dr.  Draper :  "  Let  a  man  abstain  from  water  and 
food  for  an  hour,  and  the  balance  will  prove  he  has 
become  lighter."  This  action  of  0,  so  destructive — 
wasting  us  away  constantly  from  birth  to  death — 
is  yet  essential  to  our  existence.  Why  is  this?  Here 
is  the  glorious  paradox  of  life.  We  live  only  as  we 
die.  The  moment  we  cease  dying,  we  cease  living. 
All  our  life  is  produced  by  the  destruction  of  our 
bodies.  No  act  can  be  performed  except  by  the 
wearing  away  of  a  muscle.  No  thought  can  be 
evolved  except  at  the  expense  of  the  brain.  Hence 
the  necessity  for  food  to  supply  the  constant  waste 
of  the  system,*  and  for  sleep  to  give  nature  time  to 
repair  the  losses  of  the  day.  Thus,  also,  we  see  why 
we  feel  exhausted  at  night  and  refreshed  in  the 
morning. 

0  the  Common  Scavenger. — God  has  no  idlers  in 
His  world.  Each  atom  has  its  use.  There  is  not  an 
extra  particle  in  the  universe.  The  mission  of  oxy- 
gen, so  destructive  in  its  action,  is  therefore  essen- 
tial, that  every  waste  substance  may  be  collected 
and  returned  to  the  common  stock,  for  use  in  nature's 
laboratory.    In  performing  this  general  task,  its  uses 

*  This  food  must  be  organic  matter  endowed  with,  potential  energy 
treasured  up  in  the  plant.  When  it  is  transformed  into  flesh,  perhaps 
made  still  more  vital  in  the  process,  we  have  this  power  standing  ready  to 
be  used  again  at  our  pleasure.  When  we  will  it,  the  O  combines  with  the 
flesh  and  sets  free  the  energy  for  us  to  apply. 


22  INORGANIC     CHEMISTRY. 

are  most  important  and  necessary.  It  sweetens  water, 
it  keeps  the  avenues  of  the  body  open  and  unclogged,* 
it  preserves  the  air  wholesome.  It  becomes,  in  a  word, 
the  universal  scavenger  of  nature.  Every  dark  cellar 
of  the  city,  every  recess  of  the  body,  every  nook  and 
cranny  of  creation,  finds  it  waiting ;  and  the  instant 
an  atom  is  exposed,  the  oxygen  seizes  upon  it.  A 
leaf  falls,  and  its  destruction  forthwith  commences. 
A  tiny  twig,  far  out  at  the  end  of  a  limb,  dies,  and 
the  0  immediately  begins  its  removal.  A  pile  of  de- 
caying vegetables,  a  heap  of  rubbish,  the  dead  body 
of  an  animal,  a  fallen  tree,  the  houses  we  build  for 
our  shelter,  even  the  monuments  erected  above  our 
final  resting-place,  are  all  gnawed  upon  by  what  we 
call  the  "  insatiate  tooth  of  time."  It  is  only  the 
constant  corrosion  of  this  destructive  agent — oxygen. 
Consumption  of  0. — Each  adult  uses  daily  1^  lbs. 
of  O.  The  combustion  of  1  lb.  of  coal  requires 
2f  lbs.  of  0:  so  that  the  ship  which  burns  1,000 
tons  in  crossing  the  ocean,  takes  out  of  the  air 
2,666  tons  of  0.  Supposing  the  population  of  the 
earth  to  be  1,200,000,000,  and  each  person  to  con- 
sume 1  lb.  of  0  ;  adding  as  much  more  to  sustain 
fires ;  twice  as  much  for  the  wants  of  animals,  and 
four  times  as  much  for  the  varied  processes  of  de- 
cay, the  daily  consumption  of  0  reaches  the  enor- 
mous sum  of  4,800,000  tons  (Faraday).  Yet  the 
atmosphere  contains  over  one   quadrillion   tons,  and 


•  Huxley  very  prettily  calls  O.  in  this  connection,  the  "great  sweeper" 
of  the  body,  since  it  lays  hold  of  all  the  waste  matter  of  the  system,  and 
burning  it  up,  removes  it  out  of  the  way. 


O  Z  O  K  E . 


23 


even  this  vast  aggregate  is  a  mere  fraction  compared 
with  the  0  locked  up  in  the  ocean  and  the  rock. 

Results  if  the  Air  were  Undiluted  0.  —  The  fire 
element  would  run  riot  every-where.  JMetal  lamps 
would  burn  with  the  oil  they  contain.  Our  stoves 
would  blaze  with  a  shower  of  sparks.  A  fire  once 
kindled  would  spread  with  ungovernable  velocity, 
and  a  universal  conflagration  would  quickly  wrap 
the  world  in  flame.  W' 


Fig.  5. 


OZONE. 

Ozone  is  an  allotropic  form  of  0 — i.  c,  a  form  in 
which  the  element  itself  is  so  changed  as  to  have 
new  properties. 

Source. — It  is  always  perceived  during  the  work- 
ing of  an  electric  machine,  and  is  then  called  "the 
electric  smell."  It  is  also  said 
to  have  been  noticed  dur- 
ing thunder-showers,  and  is 
formed  by  evaporation  and 
various  processes  of  combus- 
tion. 

Preparation.  —  Place  a 
freshly  scraped  stick  of  phos- 
phorus in  a  jar  containing  a 
little  water,  so  that  it  shall 
be  partly  covered  with  the 
water.  It  will  slowly  oxidize, 
and  the  peculiar  odor  of  ozone 

will  soon  be  perceived  in  the  jar.    It  may  also  be  tested 
by   a  paper  wet   with   a   mixture  of  starch   and  po- 


Tisling  ozone. 


24  INORGANIC    CHEMISTRY. 

tassium  iodide  (KI).  The  ozone  sets  free  the  iodine, 
which  unites  witli  the  starch,  forming  blue  iodide 
f)f  starch.*  At  a  temperature  above  that  of  boiling 
watei',  the  ozone  will  tiu'n  back  into  0. 

Properties. — Ozone  is  still  more  corrosive  than 
oxygen.  It  tarnishes  mercury,  which  oxygen  does 
not  attack  at  ordinary  temperatures ;  it  bleaches 
powerfully,  and  it  is  a  rapid  disinfectant.  A  piece 
of  tainted  meat  plunged  into  a  jar  of  it  is  instantly 
deodorized,  and  it  is  probable  that,  even  in  minute 
quantities,  this  gas  exercises  a  powerful  influence  in 
purifying  the  atmosphere.  Ozone  is  condensed  oxygen. 
Its  molecule  consists  of  three  atoms  of  0  instead  of 
two,  as  in  ordinary  oxygen.  The  change  of  oxygen 
into  ozone  may  be  thus  represented : 
3O2      =      2O3 

Oxygen  Ozone. 

WEIGHING    AND    MEASURING    GASES. 

It  is  so  much  easier  to  measure  the  volume  of  a 
gas  than  it  is  to  weigh  it,  that  in  practice  the  gas 
obtained  by  any  reaction  is  usually  measured  and 
its  amount  or  weight  calculated  from  its  volume. 
But  since  a  given  quantity  of  any  gas  by  weight  occu- 
pies a  different  volume  at  different  temperatures  and 
at- different  pressures,  both  temperature  and  pressure 
(height  of  barometer)  at  the  time  of  measuring,  have 
to  be  taken  into  account  in  making  the  calculation. 
The  law  for  the  change  in  volume  produced  by  tem- 

*  If  a  piece  of  the  dry  iodized  paper  be  exposed  upon  a  clear  day  to 
the  open  air  of  the  country,  in  a  few  minutes  it  will  assume  a  bluisli  tint. 
In  cloudy,  foggy  weather,  or  in  cities,  this  effect  is  rarely  observed. 


WEIGHING     AND     MEASURING     GASES.  25 

perature  is  : — a  gas  expands  or  contracts  ^\^  part  of 
the  volume  it  ivould  have  at  0°C.,  for  every  change 
of  one  degree  centigrade  in  its  temperature.  Hence, 
if  F"  be  the  volume  of  a  gas  measured  at  0°C.,  and  r 

the  volume  it  would  assume  at   t°C.,    v  —  V  -\-  -^-=-^V. 

If  r  be   the  volume   at   t°C.,  the  volume  at   0°C.,  or 

T--        273 

~  "^273  +  ^ 

The  law  for  the  effect  of  pressure  is : — the  volume 
of  a  gas  varies  inversely  as  the  pressure.  Hence,  if 
the    volume    is    T"  under    pressure    P   and   r   under 

pressure  p,   V  :  v  : :  p  :  P ;   and  V=  -p-  or  i;  = . 

The  pressure  is  stated  in  millimeters,  and  refers 
to  the  height  of  a  column  of  mercury  (barometer) 
which  the  pressure  would  sustain.  760  mm.  is  taken 
as  the  standard  pressure,  and  0°C.  as  the  standard 
temperature. 

When  the  weight  of  a  liter  of  any  gas  under 
standard  conditions  is  known,  the  weight  of  any 
volume  measured  under  any  known  conditions  may 
be  readily  calculated.  The  steps  of  the  calculation 
are :  Ist.  Find  what  the  volume  would  be  under 
standard  conditions  by  means  of  the  formulas  given 
above.  2d.  Multiply  this  result  by  the  weight  of  one 
liter  of  the  gas  under  these  standard  conditions. 

By  .means  of  our  chemical  equations  we  can  find 
the  weight  of  a  gas  which  a  given  weight  of  the 
re-agents  will  produce  (see  p.  12).  Now,  the  volume 
which    this   weight   of    gas   will    occupy   under    any 


26  INORGANIC     CHEMISTRY. 

pressure  and  at  any  temperature,  may  be  found  by 
the  following  steps: — 1st.  Divide  the  weight  of  the 
gas  by  the  weight  of  our  "  standard  "  liter — this  gives 
the  volume  under  standard  conditions.  2d.  Find  the 
volume  at  the  given  temperature  and  pressure  by 
the  use  of  the  formulas. 

In  this  way  we  can  find  out  exactly  how  many 
liters  of  a  gas  {e.g.,  0),  measured  at  the  temperature 
of  the  room  and  under  the  existing  atmospheric 
pressure,  can  be  obtained  from  a  given  weight  of  the 
substance  used  for  its  production  {e.g.,  KCIO3). 


PRACTICAL    QUESTIONS. 

1.  What  becomes  of  the  v.'ater  that   "  dries  up "  ?     Of  the  wood  that 
"  burns  up  "  ?    Is  there  any  destruction  of  the  matter  they  contain  * 

2.  Where  is  the  higher  oxide  formed,  at  the  forge  or  in  the  pantry? 

3.  Why  is  the  blood  red  in  the  arteries,  and  dark  in  the  veins? 

4.  Do  we  need  more  O  in  winter  than  in  summer? 

5.  Which  would  starve  sooner,  a  fat  man  or  a  lean  one? 

6.  How  do  teamsters  warm  themselves  by  slapping  their  hands  together? 

7.  Could  a  person  commit  suicide  by  holding  his  breath? 

8.  Why  do  we  die  when  our  breath  is  stopped? 

9.  Why  do  we  breathe  so  slowly  when  we  sleep? 

10.  How  does  a  cold-blooded  animal  differ  from  a  wann-blooded  one? 

11.  Why  does  not  the  body  burn  out  like  a  candle? 

12.  Do  all  parts  of  the  body  change  alike? 

13.  WTiat  objects  would  escape  combustion  if  the  air  were  undiluted  O  ? 

14.  "VMiy  is  it  difficult  to  obtain  O  from  the  air? 

15.  What  weight  of  O  can  be  obtained  from  10  grams  of  HgO? 

16.  How  much  O  can  be  obtained  from  6  grams  of  KCIO3? 

17.  How  much  KCIO3  would  be  needed  to  produce  2  kilograms  of  O? 

18.  How  much  KCl  would  >)e  formed  in  preparing  1  kilogram  of  O  ? 

19.  Is  it  probable  that  all  the  elements  are  discovered  ? 

20.  Is  heat  produced  by  oxidation? 

21.  What  is  the  difference  between  kinetic  and  potential  energy  ? 
28.  Why  docs  running  cause  jjanting? 

23.  How  does  O  give  us  strength? 

24.  Does  the  plant  produce  energj'  ? 

25.  If  we  bum  an  organic  body  in  a  stove  it  gives  off  heat;  in  the  body 
it  produces  also  motion.    Explain. 


NITROGEN.  27 

26.  MTiy  does  not  blowing  cold  air  on  a  fire  with  a  bellows  extinguish  it  ? 

27.  Why  does  blowing  on  a  fire  kindle  it,  and  on  a  lighted  lamp  ex- 
tinguish it? 

28.  Why  can  we  not  ignite  hard  coal  with  a  match? 

29.  Why  wiU  an  excess  of  coal  put  out  a  fire? 

30.  Could  a  light  be   frozen  out,  i.e.,  extinguished,  by  merely  lowering 
the  temperature  ? 

31.  Why  is   it  beneficial  to  stir  a  wood-fire,  but  not  one  of  anthracite 
coal? 

32.  Why  will  water  put  out  a  fire  ? 

33.  What  should  we  do  if  a  person's  clothes  take  fire? 

34.  Ought  the  doors  of  a  burning  house  to  be  thrown  open? 

35.  How  much  O  can  be  obtained  from  100  grams  of  HgO? 

36.  What  would  be  the  volume  of  the  O  of  Question   35  under  the 
standard  conditions?* 

37.  What  would  be  the  volume  of  the  O  at  12"  C.  and  under  a  pressure 
of  740  mm.  of  mercury? 

38.  What  woiHd  be  the  volume  of  the  O  of  Question   16   at  20°  C.  and 
750  mm.  ? 

39.  How  much  KCIO3  must  be   employed   to   make   an   amount  of  O 
which  shall  measure  100  liters  at  18°  C.  and  760  ?«?«.? 


,,  NITROGEN. 

Symbol,  N Atomic  Weight,  14 Specific  Gravity,  0,97.     . 

■J  This  gas   is   called   nitrogen   because   it   exists  in 
niter. 

Occurrence. — N  forms  about  4  of  the  atmosphere, 
and  is  found  abundantly  in  nitrates  {e.g..,  saltpeter), 
ammonia,  flesh, f  and  in  such  vegetables  as  the  mush- 
room, cabbage,  horse-radish,  etc.  It  is  an  essential 
constituent  of  the  valuable  medicines,  quinine  and 
morphine,  and  of  the  potent  poisons,  prussic  acid 
and  strychnine. 

*  The  weight  of  a  liter  of  O  under   standard   pressure   and  at  standard 
temperature  is  1.43  gram. 

t  Its  compounds  give  to  burnt  hair  and  woolen  their  peculiar  odor. 


28 


INORGANIC     CHEMISTRY 


Fig.  6. 


Prepanng  N. 


Preparation. — As  the  air  consists  almost  exclusively 
of  N  and  0,  the  easiest  method  of  obtaining  the  former 
gas  is  to  remove  the  latter  by  employing  it  to  oxidize 
some  substance.  The  substance  should  be  one  which 
forms  an  oxide  which  is  solid,  liquid,  or  readily  soluble, 

so  that  no  gaseous  prod- 
uct may  be  left  mixed 
with  the  N.  Place  in  the 
center  of  a  deep  dish  of 
water  a  little  stand  sev- 
eral inches  in  height,  on 
which  a  bit  of  phos 
phorus  may  be  laid  and 
ignited.  As  the  fumes 
of  phosphorus  pentoxide 
ascend,  invert  a  receiver 
over  the  stand.  The  phosphorus  will  consume  the  0 
of  the  air  contained  in  the  jar,  leaving  the  N.  After 
the  jar  has  cooled  it  will  be  found  that  the  N  occu- 
pies I  of  the  receiver.  The  jar  will  at  first  be  filled 
with  white  fumes  (P2O5),  but  they  will  be  absorbed 
by  the  HgO  in  a  short  time. 

Properties. —  N  is  of  an  entirely  negative  charac- 
ter. It  is  colorless,  odorless,  and  tasteless.  It  neither 
burns  nor  permits  any  thing  else  to  burn.  A  candle 
will  not  burn  in  it,  and  a  person  can  not  breathe  it 
alone  and  live,  simply  because  it  shuts  off  the  life- 
giving  0.  80  will  a  person  drown  in  H2O  not  that 
the  water  poisons  him,  but  because  it  fills  his  mouth, 
and  shuts  out  the  air.  N  hns  only  a  weak  affinity 
for  any  of  the  elements.    The  instability  of  its  com- 


NITROGEN.  29 

pounds  is  a  striking  peculiarity.  It  will  unite  with 
iodine,  for  example,  but  a  brush  with  a  feather,  or 
a  heavy  step  on  the  floor,  will  set  it  free.* 
v  Uses.  —  Relation  of  N  to  Organic  Substances. — 
Four  fifths  of  each  breath  that  enters  our  lungs  is 
N  ;  yet  it  comes  out  as  it  went  in,t  while  that  por- 
tion of  the  0  which  remains  behind  performs  its 
wonderful  work  within  our  bodies.  About  one  sixth 
of  our  flesh  is  N,  yet  none  of  it  comes  from  the  air 
we  breathe.  We  obtain  all  our  supply  froin  the  lean 
meat  and  vegetables  we  eat.  Plants  breathe  the  air 
through  the  leaves — their  lungs ;  yet  they  appro- 
priate but  little  of  the  N  obtained  in  this  way,  and 
rely  upon  the  ammonia  and  the  nitric  acid  their 
roots  absorb  from  the  soil.  N  enters  the  stove  with 
the  0 — the  latter  unites  with  the  fuel ;  but  the  former, 
having  no  chemical  attraction,  passes  out  of  the 
chimney.  Even  from  a  blast-furnace,  where  Fe  melts 
like  wax,  N  comes  forth  without  the  smell  of  fire 
upon  it  (p.  152).  So  inert  is  it,  that  it  will  not  unite 
directly  with  any  organic  substance.  We  must  all, 
animals  and  plants,  depend  upon  finding  it  already 
combined  in  some  chemical  compound,  and  so  appro- 
priate it  to  our  use.     But  even  then  we  hold  it  very 

*  "Like  a  half -reclaimed  gypsy  from  the  wilds,  it  is  ever  seeking  to  be 
free  again ;  and  not  content  with  its  own  freedom,  is  ever  tempting  others, 
not  of  gypsy  blood,  to  escape  from  thralldom.  Like  a  bird  of  strong  beak 
and  broad  wing,  whose  proper  place  is  the  sky,  it  opens  the  door  of  its 
aviary,  and  rouses  and  flutters  the  other  and  more  peaceful  birds,  till  they 
fly  with  it,  although  they  soon  part  company."— £Wiw6Mr(/^  Review. 

+  There  is  a  constant  though  minixte  exhalation  of  N  through  the  pores 
of  the  skin.  This  small  amount  is  perhaps  absorbed  in  the  lungs,  but  it  is 
of  no  use  to  the  body,  so  far  as  known. 


30  INORGANIC     CHEMISTRY. 

loosely  indeed.  The  tendency  of  flesh  to  decompose 
is  largely  owing  to  the  instability  of  nitrogen  com- 
pounds. 

Difference  between  N  and  0.'^' — We  see,  now,  how 
different  N  is  from  0.  The  one  is  the  conservative 
element,  the  other  the  radical.  But  notice  the  nice 
planning  shown  in  the  adaptation  of  the  two  to  cmr 
wants.  0,  alone,  is  too  active,  and  must  be  re- 
strained ;  N,  alone,  is  sluggish,  and  fit  only  to  weaken 
a  stronger  element.  "Were  the  air  undiluted  0,  our 
life  would  be  excited  to  a  pitch  of  which  we  can 
scarcely  dream,  and  would  sweep  through  its  fever- 
ish, burning  course  in  a  few  days;  were  it  undiluted 
N  we  could  not  exist  a  moment.  Thus  we  see  that, 
separately,  either  element  of  the  air  would  kill  us, 
0  by  excess  and  N  by  lack  of  action. 

0  and  N  combined. — A  mixture  of  the  active  0  and 
the,  inert  N  gives  us  the  goklen  mean.  The  0  now 
quietly  burns  the  fuel  in  our  stoves  and  keeps  us 
warm ;  combines  with  the  oil  in  our  lamps  and  gives 
us  light ;  acts  upon  the  materials  of  our  bodies  and 
gives  us  warmth  and  strength  ;  cleanses  the  air  and 
keeps  it  fresh  and  invigorating ;  sweetens  foul  water 
and  makes  it  wholesome ;  works  all  around  and  within 
us  a  constant  miracle,  yet  with  such  delicacy  and 
quietness  that  we  never  perceive  or  think  of  it  until 
wo  see  it  with  the  eye  of  science. 

Compounds.  —  Nitric  Acid,  HNO3.  —  Sources.  —  This 

♦  The  difference  between  these  two  gases  can  be  best  illustrated  by 
having  a  jar  of  each,  and  rapidly  passing  a  lighted  candle  from  one  to  the 
other ;  the  N  will  extinguish  the  flame,  and  the  O  relight  thQ  coal.  By 
dexterous  management,  this  may  be  repeated  a  score  of  times. 


NITROGEN. 


31 


compound  of  H,  N,  and  0  can  not  be  easily  made  by 
the  direct  union  of  its  elements,  on  account  of  the 
inert  character  of  N  ;  but  compounds  closely  allied 
to  it  are  formed  in  favorable  soils  by  the  decompo- 
sition of  the  waste  products  of  animal  life.  These 
compounds  contain  a  metal,  usually  K  or  Na,  in  place 
of  the  H,  and  are  called  nitrates — e.g.,  KNO3,  potas- 
sium nitrate;    NaNOs,  sodium  nitrate. 


Fig.  7, 


Preparing  HNO3. 

Preparation. — Nitric  acid  is  prepared  by  treating 
a  nitrate  with  a  stronger  acid.  Thus,  if  sulphuric 
acid  (H2SO4)  and  sodium  nitrate  be  gently  heated 
together  in  a  retort,  nitric  acid  will  distil  over  and 
can  be  collected  in  a  receiver,  cooled  by  dripping 
water. 

The  chemical  reaction  may  be  represented  thus: 
V      2NaN03  +  H2SO4  =  NaaSO^  +  2HNO3. 

Properties. — It  is  an  intensely  corrosive,  poisonous 
liquid.  When  pure,  it  is  colorless ;  but  as  sold,  it  has 
commonly   a   golden   tint  from   the   presence   of   an 


32  INORGANIC     CHEMISTRY. 

oxide  of  N,  produced  by  the  decomposing  action  of 
the  light.  In  strength  it  is  next  to  H2SO4..  It  dis- 
solves most  metals  with  the  formation  of  nitrates. 
It  was  formerly  called  aqua  fortis,  or  strong  water. 
It  stains  wood,  the  skin,  etc.,  a  bright  yellow.  Both 
nitric  acid  and  nitrates  give  up  their  0  readily,  and 
hence  are  powerful  oxidizing  agents.* 

Uses. — HNO3  is  employed  in  dying  silk  yellow,  in 
making  gun-cotton,  nitro-glycerin,  and  other  explo- 
sives, and  in  surgery  for  cauterizing  the  flesh.  In 
combination  with  HCl,  it  forms  aqua  regia,  the  usual 
solvent  of  Au.  It  etches  the  lines  in  copper-plate 
engraving,  and  the  beautiful  designs  on  the  blades 
of  razors,  swords,  etc.  The  process  is  very  simple  : 
the  surface  is  covered  with  a  varnish  impervious  to 
the  acid,  and  the  desired  figure  is  then  sketched 
in  the  varnish  with  a  needle.  The  HNO3  being 
poured  on,  dissolves  the  metal  in  the  delicate  lines 
thus  laid  bare. 

Nitrous  Oxide,  NgO.  —  Preparation.  —  This  gas  is 
made  by  heating  ammonium  nitrate  (NH4NO3),  which 
decomposes  into  2H2O  and  NjO.     (See  p.  33.) 

Properties. — N2O    is    a    colorless,   transparent    gas 

*  The  following  experiments  illustrate  this  property: 

1.  IVIix  equal  parts. of  strong  HNO3  and  HjSO,.  Place  a  little  oil  of 
turpentine  in  a  cup  out-of-doors,  and  pour  the  mixture  upon  it  at  arm's 
length.    The  turpentine  will  burn  with  almost  explosive  violenee. 

2.  Pour  dilute  IINO3  upon  bits  of  tin.  Dense,  red  fumes  (NOj,  nitric 
peroxide)  \\'ill  pass  off,  and  the  Sn  will  be  conveited  into  a  white  oxide, 
which  furnishes  what  is  termed  putty  powder. 

3.  Throw  crystals  of  any  nitrate  on  red-hot  coals.  They  will  deflagrate 
on  account  of  the  O  which  they  give  up  to  the  fire. 

4.  SoaK  a  strip  of  blotting-paper  in  a  solution  of  niter.  It  will  form 
"touch-paper,"  and  when  lighted  will  only  smolder. 


NITROGEN. 


33 


Fig.  8. 


Preparing  N^O. 


with  a  faintly  sweetish   taste  and  smell.    It  is  some- 
what  soluble   in  water,   so   that  there   is   some   loss 
when   it  is   collected   over   water.    It   supports   com- 
bustion   nearly    as 
well  as  0,  and  many 
of  the  experiments 
ordinarily    p  e  r  - 
formed      with      0 
wiU  be   almost    as 
brilliant  with  NgO. 
If   breathed   for    a 
short  time,  it  pro- 
duces    a     peculiar 
kind    of    intoxica- 
tion, often  attended 

with  uncontrollable  laughter,  and  hence  it  has  re- 
ceived the  popular  name  of  laughing  gas.  The  effect 
soon  passes  off.  If  taken  for  a  longer  time,  it  causes 
insensibility,  and  is  therefore  valuable  as  an  anaes- 
thetic in  minor  surgical  operations,  as  in  pulling  teeth. 

Nitric  Oxide,  NO. — Preparation. — This  gas  may  be 
prepared  by  the  action  of  dilute  HNO3  on  copper 
clippings.  The  flask  (o,  Fig.  0)  will  soon  be  filled 
with  red  fumes,  but  a  colorless  gas  will  collect  in 
the  jar  over  water.  At  the  conclusion  of  the  process, 
the  flask  will  contain  a  deep  blue  solution  of  copper 
nitrate  (CU2NO3).  By  filtering  and  evaporating,  the 
beautiful  crystals  of  this  salt  may  be  obtained. 

There  are  two  changes  involved  in   the   reaction  ; 
in  the  first,  copper  nitrate  is  formed  and  H  set  free  : 
Cu  +  2HNO3  =  CuaNOg  +  2H  ; 


34 


INORGANIC     CHEMISTRY. 


and  then   the  H  is  oxidized  by  the   nitric  acid  with 
the  production  of  water  and  NO  : 

2HNO3  +  6H  =  4H2O  +  2N0. 


FiQ.  9. 


Preparing  NO. 

Properties. — NO  is  a  colorless,  irrespirable  gas  with 
a  disagreeable  odor.  It  does  not  burn,  nor  does  it 
support  combustion,  although  it  contains  twice  as 
much  0  as  NjO.  This  shows  that  the  0  is  held  more 
firmly  than  in  the  latter  gas.  Its  remarkable  prop- 
erty is  its  affinity  for  0.  Let  a  bubble  escape  into 
the  air,  and  red  fumes  of  nitric  peroxide  (NO2)  will 
be  formed.* 


*  This  may  be  illustrated  still  moi-e  prettily  by  the  following  experi- 
ment:—Fill  a  small  jar  with  water  colored  blue  by  litmus  solution,  and 
pass  up  into  it  siifficient  NO  to  occupy  about  one  third  of  the  bottle ;  the 
litmus  will  not  change  in  color.  Now  allow  a  few  bubbles  of  O  to  rise  into 
the  NO ;  deep  red  fumes  will  be  foi-med,  which  will  quickly  dissolve,  and 
the  blue  solution  become  red.  If  both  the  O  and  the  NO  be  pure,  it  is 
IK)8sible,  by  cautiously  adding  O,  to  cause  a  complete  absorption  of  both 
gases.  If  common  air  were  used  instead  of  O,  only  N  would  then  remain 
in  the  jar. 


NITROGEN. 


35 


Pig.  10. 


Ammonia,  NH3. — Source. — This  gas  was  formerly 
called  hartshorn,  because  in  England  it  was  made 
from  the  horns  of  the  hart.  It  received  the  name 
ammonia^  by  which  it  is  now  more  generally  known, 
from  the  temple  of  Jupiter  Ammon,  near  which  sal- 
ammoniac,  one  of  its  compounds,  was  once  manu- 
factured. The  aqua  am- 
monia of  the  shops, 
which  is  merely  a  strong 
solution  of  the  gas  in 
H2O,  is  obtained  from 
the  incidental  products 
of  the  gas-works  in  large 
quantities.  (See  p.  72.) 
Its  pungent  odor  can 
often  be  detected  near 
decaying  vegetable  and 
animal  matter. 

Preparation.  —  NH3  is 
ordinarily  prepared  by 
heating  sal-ammoniac 
with  lime.*  The  reac- 
tion may  be  represented  as  follows : 

2NH^.C1  +  CaO  =  2NH3  +  HgO  +  CaClg. 

It  is  also  conveniently  obtained  for  experiments  by 
gently  heating  aqua  ammonia. 

Properties. — NH3  is  a  colorless  gas,  having  a  pecul- 
iar pungent  and  suffocating  odor,  and  a  caustic  taste. 

*  This  may  be  illustrated  by  simply  mixing  in  a  cup  some  powdered  sal- 
am^moniac  (ammonium,  chloride)  and  lim^e  (calcium  oxide),  when  the  ammo- 
nia may  be  detected  by  its  odor,  and  the  bluing  of  moist  red  litmus-paper. 


Preparing  NH3. 


36 


INORGANIC     CHEMISTRY. 


It  can  be  readily  condensed  to  a  liquid  by  cold  or 
pressure.  When  liquefied  by  pressure,  it  passes  rap- 
idly back  into  the  gaseous  state  when  the  pressure 
is  removed,  and   in   doing  so,  absorbs  so  much  heat 

Fig.  11. 


Adsorption  of  HH^  in  zvater. 

that  water  can  be  frozen.*  NH3  will  not  support 
combustion,  nor  will  it  burn  in  air  under  ordinary 
conditions ;  but  it  burns  in  0  with  a  pale  yellow 
flame.     It  dissolves  very  freely  in  Avater,t  forming  a 

*  Carry's  inachine  foi-  making  artificial  ice  makes  use  of  these  facts. 
For  a  doscription  of  this  see  Roscoe  and  Schorlemmer,  under  Ammonia. 

t  Heat  a  little  aqua  ammonia  in  a  flask.  Dry  the  vapor  and  collect  in 
an  inverted  bottle,  for  which  a  cork  and  tube,  with  the  inner  extremity 
drawn  to  a  fine  point  over  the  spirit  lamp,  has  been  provided.  Insert 
the  cork,  and  then  plunge  the  bottle  into  a  vessel  of  water.  The  water 
which  passes  in  first  will  absorl)  the  gas  so  quickly  as  to  make  a  par- 
tial vacuum,  into  which  the  water  will  rush  so  violently  as  to  produce  a 
miniature  fountain.  If  the  water  is  colored  with  a  little  red  litmus,  it 
wiU  turn  blue  as  it  enters  the  bottle- 


NITROGEN. 


37 


solution   which   smells   strongly   of  '^^^-  ^^■ 

the  gas,  and  from  which  it  can  be 
all  driven  off  by  heat. 

Nascent  State.— Though  N  and  H, 
if  mixed  in  a  receiver,  will  not  unite 
chemically  without   the  agenc,y  of 
heat  or  electricity,  in  the  decomposi- 
tion of  organic  substances  containing 
N  and  H.  these  elements  often  combine 
to  form  N  H  3.    Other  elements  show  a 
very  similar  difference  in  chemical 
activity.   It  is  therefore  supposed  that 
elements,  in  the  act  of  being  set  free 
from  their  compounds,  have  a  peculiar  chemical  ac- 
tivity, and  are  then  said  to  be  in  the  "nascent  state." 


KH3  buininy  in  O. 


PRACTICAL     QUESTIONS. 

1.  How  could  you  detect  any  free  O  in  a  jar  of  N? 

2.  How  would  you  remove  the  product  of  the  test? 

3.  In  the  experiment  shown  in  Fig.  9,  why  is  the  gas  red  in  the  flask, 
but  colorless  when  it  bubbles  up  into  the  jar? 

4.  How  much  NH3  can  be  obtained  from  3  grams  of  sal-ammoniac? 

5.  What  will  be  the  volume  of  the  NH3  at  20°  C.  and  770  mm.  1 

6.  How  much  H,0  will  be  formed  in  the  process? 

7.  How  much  CaO  will  be  needed? 

8.  How  much  NjO  can  be  made  from  1  gram  of  ammonium  nitrate? 

9.  How  much  nitric  acid  can  be  foi'med  from  50  kilos  of  sodium  nitrate 
(XaNOo)  ? 

10.  Wliat  causes  flesh  to  decompose  so  much  more  easily  than  wood? 

11.  If  a  tuft  of  hair  be  heated   in  a  test  tube,  the   liquid   formed  will 
turn  red  litmus  paper  bkie.    Explain. 

12.  Why  should  care  be  used  in   opening  a  bottle  of  strong  NH3  in  a 
warm  room? 

13.  What  weight  of  X  is  there  in  10  grams  of  HNO3? 

14.  How  much  sal-ammoniac  would  be  required  to  make  20   liters  of 
NH3  measured  at  25°  C.  and  744  ww.? 

15.  What  is  the  difference  between  liquid  ammonia  and  liquor  ammoniae  ? 


38 


INORGANIC     CHEMISTRY. 


H  Y  D  R-OG  E  N. 

Symbol,  H Atomic  Weight,  1 Specific  Gravity,  .069. 

Hydrogen  means  literally  a  generator  of  water. 
Occurrence.  —  H    forms   one   ninth    the   weight   of 
water,  and  is  a  constituent  of  all  animal  and  vegeta- 
ble substances. 

Fio.    13. 

Preparation.  —  It  may 
be  obtained  from  water  by 
means  of  the  electric  cur- 
rent, or  by  the  action  of 
certain  metals.  If  an  elec- 
tric current  be  led  through 
acidulated  water,  H  is  given 
off  at  the  negative  pole 
and  0  at  the  positive  pole. 
If  a  small  piece  of  sodium 
is  thrown  on  water,  it 
melts  and  rolls  over  its  surface  like  a  tiny  silver 
ball.  If  the  water  be  heated,  the  ball  bursts  into  a 
bright  yellow  blaze.  If  potassium 
be  used  instead  of  sodium,  the  H 
catches  fire  at  once,  even  on  cold 
water,  and  burns  with  some  vola- 
tilized K,  which  tinges  the  flame 
with  a  beautiful  purple  tint.*  If 
the  water  be  examined  after  the  action  is  over,  it 
IS  found  to  feel  soapy,  to  turn  red  litmus  paper  blue. 


Fiepariiiij  I'lydrogen. 


Fig.  14. 


K  on  HaO. 


•  Cut  the  metal  in  small  pieces  and  cover  it  with  wire  gauze,  since  the 
melted  globule  bursts  at  the  close  of  the  experiment. 


HYDROGEN.  39 

and  to  leave,  on  evaporation,  a  white  substance. 
This  wliite  substance  is  KOH  or  NaOH,  potassium  or 
sodium  hydroxide.  The  formation  of  this  substance 
and  of  H  by  the  action  of  Na  on  water  is  represented 
as  follows : 

H2O  +  Na  =  NaOH  +  H. 

The  H  made  in  this  waj^  may  be  collected  in  an 
inverted  test  tube  full  of  water  by  imprisoning  the 
globule  of  Na  in  a  cage  of  wire  gauze  beneath  the 
mouth  of  the  tube. 

H  is  usually  prepared  from  sulphuric  acid  (H2SO4) 
by  the  action  of  zinc.    The  reaction  is  as  follows  : 

H2SO4  +  Zn  +  H2O  =  ZnS04  +  H2O  +  2H. 

The  ZnS04  (zinc  sulphate)  is  contained  in  the  solu- 
tion which  remains,  and  may  be  obtained  in  crystals 
by  evaporating  off  the  water.  With  strong  H2SO4 
other  reactions  occur. 

Properties. — H  prepared  in  this  manner  has  a  dis- 
agreeable odor,  from  impurities  which  it  contains.* 
When  pure,  it  is,  like  0,  colorless,  transparent,  and 
odorless.  It  is  the  lightest  of  all  bodies,  being  four- 
teen and  a  half  times  lighter  than  air,  and  sixteen 
times  lighter  than  0.  It  is  not  poisonous,  although, 
like  N,  it  will  destroy  life  by  shutting  out  the  life- 
sustainer,  0.  When  inhaled,  it  gives  the  voice  a 
ludicrously  shrill  tone.  It  can  be  breathed  for  a  fevv^ 
moments  with  impunity,  if  it  be  first  purified.  Owing 
to   its    lightness,   it   passes    out  of    the    lungs    again 

*  This  odor  can  be  removed  by  causing  it  to  bubble  through  a  solution 
of  potassium  permanganate.    (See  Pig.  13.) 


40 


INORGANIC     CHEMISTRY 


Fig.  15. 


Fig.   1R. 


Candle  in  H. 


directly.  Its  levity  suggested  its  use  for  filling  bal- 
loons,* and  it  has  been  employed  for  that  purpose ; 
but  coal  gas,  which  contains  much  H 
and  is  cheaper,  is  now  preferred. 

Combustion  of  H. — A  lighted  candle, 
plunged  into  an  inverted  jar  of  H,  is 
extinguished,  while  the  gas 
itself  takes  fire  and  burns 
with  an  almost  invisible 
flame.  One  atom  of  the  0 
of  the  air  unites  with  two 
atoms  of  the  H,  and  the 
product  of  the  combustion  is  HgO,  which 
may  be  condensed  on  a  cold  tumbler,  held 
over  a  jet  of  the  burning  gas.  (See 
Fig.  17.)  The  apparatus  shown  in  Fig.  16 
is  a  more  simple  means  of  illustrating 
the  properties  of  H.f 

Mixed    Gases.  —  A     mixture     of    two 
parts,    by    measure,    of    H,   with    one    part   of    0,   or 
five  parts  of  common  air,  when  ignited,  will  explode 
violently.^     The   heat  generated  by  the  union   of  H 


*  We  read  in  accounts  of  fetes  at  Paris,  of  balloons  ingeniously  made 
to  represent  various  animals,  so  that  aerial  hunts  are  devised.  The  ani- 
mals, however,  persistently  insist  upon  ascending  with  their  feet  up — a 
circumstance  productive  of  great  mirth  in  the  crowd  of  spectators. 

t  Let  the  gas  escape  a  few  moments  before  lighting  it,  so  that  the  air 
may  be  driven  out  of  the  flask. 

t  The  n  gun— which  is  simply  a  tin  tube,  closed  at  one  end,  and  pro- 
vided with  a  cork  at  the  other,  haWng  a  priming-hole  at  the  side— is  used 
to  illustrate  this  fact.  It  may  be  filled  over  the  jet  of  the  evolution  flask 
(Fig.  16)  when  that  is  not  ignited.  The  gas  is  allowed  to  pass  in  until 
the  gun  is  abovit  a  fifth  full,  as  nearly  as  one  can  guess,  when  the  gun  is 
removed  and  the  gases  ignited  at  the  priming-hole. 


HYDROGEN. 


41 


Fig.   1' 


HaO  formed  by  burning  H. 

and  0  causes  the  HgO  which  is  formed  to  appear  in 
the   state   of   steam.     Immediately   after,   the   steam 

Fig.   18. 


H'Tiii!^ 


being  condensed,  a  vacuum  is  produced  and  the  par- 
ticles of   air  rushing  in   to   fill  the   empty  space,  by 


42 


INORGANIC     C  H  E  M  I  S  T  R  Y  . 


Fi(i.  li). 


their  collision  against  each  other,  cause  the  deafen- 
ing sound.  While  the  detonation  is  so  great,  the 
force  is  slight,  as  may  he  shown  by  exploding,  in  the 
hand,  soap-bubbles  blown  with  the  gases.  H  and  0 
may  be  mingled  in  the  right  proportion  for  combus- 
tion, and  kept  for  years  without  any  change  taking 
place.  The  two  gases  remain  quietly  together,  with 
no  manifestation  of  their  chemical  affinity,  until  sud- 
denly, at  the  contact  of  the  merest  spark  of  fire, 
they  rush  together  with  a  crash  like  thunder,  and 
uniting,  form  the  bland,  passive  liquid — water. 

Action  of  Spongy  Platinum. — A  piece  of  spongy 
platinum  placed  in  a  jet  of  H  will  ignite  it.  This 
curious  effect  seems  to  be  produced 
in  the  following  way :  The  H  and  the 
0  of  the  air  are  brought  so  closel}" 
together  in  its  minute  pores  that  they 
unite,  and  the  heat  thus  generated 
sets  fire  to  the  gas.  This  action  is 
nicely  shown  by  the  instrument  repre- 
sented in  Fig.  19.  It  was  formerly 
used  by  chemists  as  a  convenient  way 
of  obtaining  a  light  in  the  laboratory. 
Friction  matches  have  superseded  this 
ingenious  invention. 

Heat  of  Burning  H. — A  hydrogen  flame  gives  little 
light,  but  great,  heat.  In  H  and  0,  existing  as  gases, 
there   is   stored   a  vast   amount   of  potential   energy. 

♦  Z  is  a  piece  of  zinc  suspended  in  a  solution  of  dilute  H^SO,.  At 
the  top  is  a  stopy-cock,  by  turning  which  the  gas  is  allowed  to  pass  out 
from  the  receiver/.  It  strikes  upon  a  piece  of  spongy  platinum,  and  ignites 
with  a  slight  explosion. 


Ddbereiner^s  Lamp* 


HYDROGEN. 


43 


Fig 


("Physics,"  pp.  36,  37.)  When  they  unite  by  chem- 
ical affinity,  this  energy  is  transformed  chiefly  into 
heat.  In  the  union 
of  8  grams  of  0  and 
one  gram  of  H,  suffi- 
cient heat  is  evolved 
to  raise  34,462 
grams  of  water  from 
0°  to  1°  centigrade  ; 
and  this  heat  is 
sufficient  to  do  the 
amount  of  work 
represented  by  lift- 
ing 14,612  kilo- 
grams a  meter  high. 
The  Chemical 
Harmonica.* —  The 
vibration  of  a  col- 
umn of  air  can  be 
illustrated  by  sim- 
ply holding  a  long  ^^M 
glass  tube,  by  means 

of  a  suitable   clamp,  Ilydrogui  tones. 


*  Another  illustration  of  singing  hydrogen  may  be  represented  in  the 
following  manner:  Make  a  jar  of  heavy  tin,  in  tlie  form  of  a  double  cone, 
twelve  inches  long  and  four  inches  in  diameter.  At  one  apex  fit  a  nozzle 
and  cork ;  at  the  other,  make  several  minute  openings.  Cover  the  holes 
with  sealing-wax,  and  draw  the  cork ;  then  fill  the  jar  with  H,  and  replace 
tlie  cork.  Wh.en  ready  for  use,  hold  the  jar  in  a  vertical  position,  remove 
the  wax  from  at  least  one  orifice,  ignite  the  H  at  that  point,  and  draw  the 
<:ork.  still  hold  the  jar  quietly,  and  in  a  minute  or  two  the  tiny  jet  of  H 
will  begin  to  sing  like  a  swarm  of  mosquitoes,  buzzing  and  humming  in  a 
most  aggravating  way  until,  unexpectedly,  the  fitful  music  ends  in  a  loud 
explosion. 


44  INORGANIC     CHEMISTRY. 

over  a  minute  jet  of  Lurning  H.  At  first  no  effect 
Avill  be  produced ;  but  as  Ave  slowly  introduce  the 
jet  farther  and  farther  into  the  tube,  a  faint  sound 
is  heard,  apparently''  in  the  far-off  distance.  It  grad- 
ually strengthens,  and  finally  bursts  into  a  shrill, 
continuous,  musical  note — the  key-note  of  the  heated 
column  of  air  Avithin  the  tube.  The  flame  rises  and 
falls  in  rapid  succession  without  ever  becoming 
quite  extinguished,  as  may  be  seen  by  looking  at 
its  image  in  a  revolving  mirror ;  and  the  succes- 
sion of  minute  collapses  of  the  body  of  air  around 
it  is  regulated  by  the  length  of  the  pipe.  Let  us 
noAv  place  the  tube  at  a  point  where  no  clapping 
of  hands  or  unusual  sound  will  start  it  into  song. 
Let  various  tones  be  produced  from  a  violin,  and 
we  shall  find  the  flame  responding  only  to  that 
tone  which  is  the  key-note  of  the  tube,  or  its  octave. 
The  violin  player  Avill  have  perfect  control  of  this 
musical  flame,  and  can  start,  stop,  or  throw  it  into 
violent  convulsions,  even  across  a  large  hall.  Tubes 
of  different  sizes  and  lengths  will  give  tones  of 
diverse  character  and  pitch.*  The  Avaves  of  sound 
from  the  instrument  augmenting  or  interfering 
Avith  those  in  the  tube  probably  produce  these  phe- 
nomena. 


*  The  singing  of  the  hydrogen  fl.ime  may  be  ilhistrated  by  holding 
large  tubes  of  any  kind,  over  the  flame  of  the  evolution  flaak.  .lets  of  dif- 
ferent sizes  may  be  made  by  drawing  out  glass  tubing  over  the  spirit-lamp. 
Attaching  a  jet,  by  iiulia-rubbci-  tubing,  to  the  nozzle  of  a  common  ga.s 
jiipe,  we  may  utilize  the  II  in  coal  gas,  and  at  the  same  time  secure  a 
brighter  flame  and  regulate  the  pressure  at  will.  The  singing  may  be  pro- 
duced oven  if  the  jet  and  tube  be  horizontal  or  inverted. 


WATER. 


45 


TiQ.   21. 


WATER. 

The  composition  of  HgO  is  proved  by  analysis  and 
synthesis — I.e.,  by  separating  the  compound  into  its 
elements,  and  by  combining  the  elements  to  produce 
the  compound.  We  can  analyze  it  in  the  manner 
already  shown  in  preparing  H  by  passing  through  it 
an  electric  current.  In  the  sjm- 
thetic  method,  we  mix  the  two 
gases  and  unite  them  as  we 
have  before  or  by  an  electric 
spark.  Both  methods  agree  in 
proving  that  water  is  composed 
of  two  volumes  of  H  to  one 
of  0.  But  0  is  sixteen  times 
heavier  than  H ,  volume  for  vol- 
ume, and  hence  the  composition 
of  water  by  weight  is  2  :  16 
or  1  :  8.  This  fact  is  expressed 
in  its  formula  HgO.  The  black- 
smith decomposes  Avater  when 
he  sprinkles  it  on  the  hot  coals 
in  his  forge.  The  H  burns  with  a  pale  flame,  while 
the  0  increases  the  combustion.  Thus,  in  a  fire,  if  the 
engines  throw  on  too  little  water,  it  may  be  decom- 
posed, and  add   to   the   fury  of  the   flame.*    To  "set 

*  "Xo  more  heat  is  produced  bj'  the  action  of  the  H2O,  but  it  is  in  a 
more  available  form,  for  communicating  heat.  The  steam  in  contact  with 
incandescent  charcoal  is  decomposed— the  O  going  to  the  C  to  form  CO 2, 
and  the  H  being  set  free.  If  the  C  is  abiindant,  and  the  heat  high,  the 
COa  is  also  decomposed,  and  double  its  volume  of  CO  formed.  The  inflam- 
mable, gases,  H  and  CO,  mingled  with  the  hydrocarbons  always  produced, 
are  ignited,  making  the  billows  of  flame  which  sweep  over  a  burning 
buililing."— S.  P.  Sharples. 


Atui/yds  of  uritcr. 


46  INORGANIC     CHEMISTRY. 

the  North  River  on  fire "  is  only  a  poetical  exag- 
geration. 

The  quantity  of  electricity  required  to  decompose 
a  single  grain  of  water  is  estimated  to  be  equal  to 
that  in  a  flash  of  lightning.  The  enormous  power 
necessary  to  tear  these  two  elements  from  each 
other  shows  the  wonderful  strength  of  chemical  at- 
traction.* We  thus  see,  that  in  a  tiny  drop  of  dew 
there  slumbers  the  latent  power  of  a  thunder-bolt. 

Water  in  the  Animal  World. — The  abundance  of 
water  very  forcibly  attracts  the  attention.  It  com- 
poses perhaps  four  fifths  of  our  flesh  and  blood. 
Man  has  been  facetiously  described  as  twelve  pounds 
of  solid  matter  wet  up  in  six  pails  of  water.  All 
plumpness  of  flesh,  and  fairness  of  the  cheek,  are 
given  by  the  juices  of  the  system.  A  few  ounces  of 
water  and  a  little  charcoal  constitute  the  principal 
chemical  difference  between  the  round,  rosy  face  of 
sixteen,  and  the  wrinkled,  withered  features  of  three- 
score and  ten.  To  supply  the  constant  demand  of 
the  system  for  water,  each  adult,  in  active  exercise, 
needs  about  thi-ee  pints  per  day,  or  over  half  a  ton 
annually.  (See  "Physiology,"  p.  220.)  When  we  pass 
to  lower  orders  of  animals,  we  find  this  liquid  still 
more  abundant.  Sunfishes  are  little  more  than  or- 
ganized water.  Professor  Agassiz  analyzed  one  found 
off  the  coast  of  Massachusetts,  which  weighed  thirty 
pounds,  and  obtained  only  half  an  ounce  of  dried 
fl(>sh.     Indeed,  an   entire  class  of  animals  (hydrozoa), 

*  Tlio  powor  necdeil  to  sepiirato  them  bocomeb  latent  in  the  gases  as  a 
X)otential  onortcy,  and  when  they  arc  burned  at  any  time  will  bo  set  free  as 
seusible  heat— a  form  of  kinetic  energy. 


WATER.  47 

to  which  belong  the  jelly-fish,  medusa,  etc.,  is  com- 
posed of  only  ten  parts  in  a  thousand  of  solid  matter. 
(See  ''Zoology,"  p.  269.) 

Water  in  the  Vegetable  World. — In  the  vegetable 
world  we  find  it  abundant.  Air-dried  wood  contains 
40  per  cent,  of  H2O;  bread  is  3  7  per  cent,  water; 
and  of  the  potatoes  and  turnips  cooked  for  our  din- 
ner, it  comprises  75  per  cent,  of  one  and  91  of  the 
other.  The  following  table  shows  the  proportion  in 
common  vegetables,  fruits,  and  meats : 


Mutton 76 

Beef 72 

Veal 78 

Pork 72 

Eggs 74 


Oysters 00 

Salmon 74 

Apples 85 

Carrots 88 


Beets 90 

Cabbage 80 

Cucumbers  .  .  .     .96 
Melons 90 


Water  in  the  Mineral  World. — Bodies  in  which 
the  water  is  chemically  combined  in  definite  propor- 
tions, are  often  called  hydrates.  In  the  image  which 
the  Italian  peddler  carries  through  our  streets  for 
sale,  there  is  nearly  one  pound  of  HgO  to  every  four 
pounds  of  plaster  of  Paris.  One  third  of  the  weight  of 
any  ordinary  soil  is  this  same  liquid.  In  some  bodies 
which  are  capable  of  crystallizing,  it  seems  to  deter- 
mine the  form  and  general  appearance,  and  is  called 
"the  water  of  crystallization."  If  we  heat  blue  vitriol, 
its  water  of  crystallization  will  be  driven  off,  and  it 
will  lose  its  color  and  become  white  like  flour.*  A  few 
drops  of  H2O  will  restore   the  blue.     If  we  expel  the 

*  This  may  be  easily  sliown  by  filling  the  bowl  of  a  clay  tobacco-pipe 
■with  crystals  of  the  salt,  and  heating  them  over  a  lamp  or  in  the  ftre  until 
the  water  of  crystallization  is  expelled.  Alum  may  be  made  anhydrous  in 
the  same  way. 


48  INORGANIC     CH£MISTKY. 

water  from  alum,  it  will  puff  up,  and  the  transparent 
crystals  will  dry  into  an  incoherent  mass.  Many  salts 
effloresce^  i.e.,  part  with  their  water  of  crystallization  on 
exposure  to  the  air,  and  crumble  into  a  white  powder. 

Water  as  a  Solvent.  —  Water,  having  no  taste; 
color,  or  odor  itself,  is  perfecth"  adapted  to  be  the 
general  solvent.  It  becomes  at  pleasure  sweet,  sour, 
salt,  bitter,  nauseous,  and  even  poisonous.  Had  water 
any  taste,  the  whole  art  of  cookery  would  be  changed, 
since  each  substance  would  partake  of  the  one  uni- 
versal watery  flavor. 

Pure  Water. — Rain-water,  caught  after  the  air  is 
thoroughly  cleansed  by  previous  showers,  and  at  a 
distance  from  the  smoke  of  cities,  is  the  purest 
natural  water  known.  It  is  tasteless,  yet  its  insi- 
pidity makes  it  seem  to  us  very  ill-flavored  indeed. 
We  have  become  so  accustomed  to  the  taste  of  the 
impurities  in  water,  that  they  have  become  to  us 
tests  of  its  sweetness  and  pleasantness. 

River-Water,  though  it  may  have  less  mineral 
matter  than  spring-water,  is  often  unfitted  for  drink- 
ing on  account  of  the  organic  matter  it  contains. 
Happil}^,  running  water  has  in  itself  a  certain  pui-i- 
fying  power,  owing  t(^  the  air  which  it  holds  in  solu- 
tion ;  so  that  organic  substances  are  burned  in  it  as 
certainly  as  they  would  be  in  a  stove.  Still,  in  order 
to  avoid  any  danger,  river-water  should  be  filtered 
through  charcoal  oi-  sand  before  using.* 

*  A  weak  solution  of  potassium  permanganate  is  an  excellent  test  of  the 
presence  of  organic  matter.  Place  the  water  to  be  examined  in  a  glass, 
and  add  a  few  drops  of  sulphuric  acid  and  a  little  permanganate :  if  or- 
ganic matter  is  present,  the  violet  i)ennanganate  solution  is  decolorized. 


WATER.  49 

Hard  Water.  —  As  water  percolates  through  the 
soil  into  our  wells,  it  dissolves  the  various  mineral 
matters  characteristic  of  the  locality.*  The  most 
abundant  of  these  are  lime,  salt,  and  magnesia. 
The  former  produces  a  fur  or  coating  on  the  bottom 
of  our  tea-kettles,  if  we  live  in  a  limestone  region. 
When  we  put  soap  in  such  water,  it  curdles — i.  e.,  it 
unites  with  the  lime  (CaO),  forming  a  new,  or  lime 
soap,  which  is  insoluble  in  H2O.  H2O  containing  an 
excess  of  mineral  matter,  is  unwholesome ;  yet  it  is 
probable  that  the  sparkling  hard  waters  of  the  lime- 
stone districts  are  relished,  not  only  because  they  are 
pleasant  to  the  eye  and  agreeable  to  the  taste,  but 
oil  account  of  some  hygienic  properties  in  the  excess 
of  CO2  they  contain,  and  possibly  because  the  CaO 
acts  medicinally  on  the  system. f 

It  is  a  fact  worthy  of  note  that  lime  and  oxide 
of  iron,  which  are  frequently  found  in  HgO,  the  lat- 
ter generally  in  minute  quantities,  are  both  health- 
ful ;  while  the  oxides  of  the  other  metals  are  poison- 
ous.   Were  zinc  or  barium,  for  instance,  as  common 


*  Most  of  the  water  in  our  world  is  unwholesome  for  drinking  purposes. 
On  the  great  ocean,  whose  volume  is  more  than  thirty  times  that  of  all 
the  land  above  sea-level,  there  is 

"  Water,  water  every-where 
And  not  a  drop  to  drink." 

+  The  French  authorities  are  so  well  satisfied  of  the  superiority  of  hard 
water,  that  they  pass  by  that  of  the  sandy  plains,  near  Paris,  and  go  far 
away  to  the  chalk  hills  of  Champagne,  where  they  find  water  even  harder 
than  that  of  London ;  giving  as  a  reason  for  the  preference  that  more  of 
the  conscripts  from  the  soft-water  districts  are  rejected  on  account  of  the 
want  of  strength  of  muscle,  than  from  the  hard-water  districts.  They 
conclude  that  calcareous  matter  is  favorable  to  the  formation  of  the  tisaues, 
No  positive  decision  on  this  point  is  possible. 


50  INORGANIC     CHEMISTRY. 

near  our  homes  as  iron  or  calcium,  wholesome  drink- 
ing water  would  be  rarely,  if  ever,  found. 

Sea-Water. — The  most  abundant  mineral  in  the 
ocean  is  common  salt.  Yet  sea-water  contains  traces 
of  every  substance  soluble  in  water,  Avliich  has  been 
washed  into  the  sea  from  the  surface  of  the  conti- 
nents during  all  the  ages  of  the  past.  Its  saline 
constituents  are  now  in  the  proportion  of  about  one 
part  in  twenty-eight.  This  amount  may  be  slowly 
increasing,  as  the  water  which  evaporates  from  the 
surface  is  pure.  In  this  way,  the  water  of  the  Salt 
Lake  has  become  a  strong  brine,  more  than  one  fifth 
of  its  whole  weight  consisting  of  saline  matter.  This 
condition  would  soon  disappear  if  an  outlet  were 
provided. 

Water  Atmosphere. — As  the  world  of  waters  is 
inhabited,  it  also  has  its  atmosphere.*  Inasmuch  as 
the  H2O  dilutes  the  0  in  part,  it  does  not  need  so 
much  N  as  the  common  air.  It  is  accordingly  com-  j 
posed  of  over  one  third  0  instead  of  only  one  fifth. 
The  air,  so  rich  in  0,  thus  absorbed  by  the  water, 
gives  to  it  life  and  briskness.  If  it  be  expelled  by 
boiling,  the  water  tastes  flat  and  insipid. 

Paradoxes  of  Water. — "  Cold  contracts,"  is  the  law 
of  physics ;  but  as  HgO  cools,  it  obeys  this  general  law 
only  as  far  as  39°  F.  (or  4^C.).  Then  it  slowly  ex- 
pands, cooling  down  to  32°,  its  freezing  point,  when 
its  crystals  suddenly  dart  out  at  angles  to  each  other, 


*  Fish  inhale  O  through  the  fliio  silky  fllaiiients  of  their  sills.  When  a 
fish  is  drawn  out  of  H.,0,  these  dry  up,  and  it  is  unable  to  breathe,  although 
it  is  in  a  more  plentiful  atmosphere  than  it  is  accustomed  to  enjoy. 


WATER.  51 

and  thus,  increasing  in  size  about  one  twelfth,  it  con- 
geals to  ice.  Ice  is  therefore  lighter  than  water,  and 
so  swims  on  top  ;  otherwise,  in  severe  winters,  our 
northern  rivers  would  freeze  solid,  killing  the  fish  and 
aquatic  plants.  The  longest  summer  could  not  melt 
such  an  immense  mass  of  ice.  But  now  the  blanket 
that  Nature  weaves  over  the  rivers  and  ponds  pre- 
vents the  water  beneath  from  reaching  the  freezing 
point.  We  give  to  water  such  contradictory  terms 
as  "  hard  "  and  "  soft,"  "  fresh  "  and  "  salt."  H2O  seems 
the  most  yielding  of  substances,  yet  the  swimmer 
who  falls  on  his  face,  instead  of  striking  head  fore- 
most, appreciates  the  mistake,  and  we  could  drive  a 
nail  into  a  solid  cube  of  steel  almost  as  easily  as  into 
a  hollow  one  perfectly  filled  with  H2O.  H  is  the  light- 
est substance  known,  and  0  is  an  invisible  gas ;  yet 
they  unite  and  form  a  liquid  whose  weight  we  have 
often  experienced,  and  a  solid  which  makes  a  pave- 
ment hard  like  granite.  H  burns  readily  and,  when 
mixed  with  0,  explodes  most  fearfully ;  0  supports 
combustion  brilliantly  —  yet  the  two  combined  are 
used  to  extinguish  fires.  H  or  0  in  excess  would 
destroy  life  ;  HgO  is  so  essential  to  it  that  thirst 
causes  a  lingering,  painful  death. 

Uses  of  Water. — The  uses  of  H2O  are  as  diverse 
as  they  are  practical.  Its  properties  fit  it  for  a  won- 
derful variety  of  operations  in  nature.  Its  office  is 
not  merely  to  moisten  our  lips  on  a  hot  day,  to  make 
a  cup  of  coffee,  to  lay  the  dust  in  the  street,  and  to 
sprinkle  our  gardens  ;  it  has  grander  and  more  pro- 
found uses  than  any  of  these.    Water  is  the  common 


52  INORGANIC     CHEMISTRY. 

carrier  of  creation.  It  dissolves  the  elements  of  the 
soil  and,  climbing  as  sap  up  through  the  delicate 
capillary  tubes  of  the  plant,  furnishes  the  leaf  with 
the  materials  of  its  growth.  It  flows  through  the 
body  as  blood,  floating  to  every  part  of  the  system 
the  life-sustaining  0,  and  the  food  necessary  for  re- 
pairs and  for  building  up  the  various  parts  of  the 
"house  we  live  in."  It  comes  from  the  clouds  as  rain, 
bringing  to  us  warmth  from  the  ocean  and  temper- 
ing our  northern  climate,  while  in  spring  it  floats 
the  ice  of  our  rivers  and  lakes  away  to  warmer  seas 
to  be  melted.  It  washes  down  the  mountain  side, 
leveling  its  lofty  summit  and  bearing  mineral  mat- 
ter to  fertilize  the  valley  beneath.  It  propels  water- 
wheels,  working  forges  and  mills,  and  thus  becomes 
the  grand  motive-power  of  the  arts  and  manufact- 
ures. It  flows  to  the  sea,  bearing  on  its  bosom  ships 
conducting  the  commerce  of  the  world.  It  passes 
through  the  arid  sands,  and  the  desert  forthwith 
buds  and  blossoms  as  the  rose.  It  limits  the  bounds 
of  fertility,  decides  the  founding  of  cities,  and  directs 
the  flow  of  trade  and  wealth. 


PRACTICAL     QUESTIONS. 

1.  Why,  in  filling  the  hydrogen  gun,  do  we  use  5  parts  of  common  air 
to  2  of  H,  and  only  1  part  of  O  to  2  of  H » 

2.  Why  are  coal  cinders  often  moistened  with  H^O  before  using? 

3.  What  injury  may  be  done  by  throwing  a  small  quantity  of  HaO  on 
a  fire? 

4.  Why  does  the  hardness  of  water  vary  in  different  localities? 

5.  What  causes  the  variety  of  minerals  in  the  ocean?    Is  the  quantity 
increasing  ? 

6.  Is  there  not  a  compensation  in   the    sea-plants,  fish,   etc.,   which  are 
washed  back  on  the  land? 


CARBON.  53 

7.  Since  "all  the  rivers  flow  to  the  sea,"  why  is  it  not  fxill? 

8.  What  is  the  cause  of  the  tonic  influence  of  the  sea-breeze? 

9.  When  fish  are  taken  out  of  the  water  and  thus  brought  into  a  more 
abundant  atmosphere,  why  do  they  die  ? 

10.  Do  all  fish  die  when  brought  on  land? 

H.  What  weight  of  water  is  there  in  a  hundredweight  of  sodium  sul- 
phate (Na^SO.,  lOHjO),  or  Glauber's  salt? 

12.  What  weight  of  water  in  a  ton  of  alum  (KA12S04,  ISH^O)? 

13.  How  does  the  air  purify  running  water? 

14.  WTiat  is  the  action  of  potassium  permanganate  as  a  disinfectant? 

15.  What  weight  of  H  can  be  obtained  from  a  liter  of  water? 

16.  How  much  Zn  must  lie  employed  to  obtain  100  grams  of  H  from 
H,SO.  ? 

17.  A  liter  of  H  under  standard  conditions  weighs  0.0896  gram.  "What 
volume  of  H  at  10°  C.  and  738  mm.  can  be  obtained  from  HsSO,  by  the 
action  of  8  kilos  of  Zn? 

18.  How  much  KCIO3  would  be  required  to  evolve  sufficient  O  to  burn 
the  H  produced  by  the  decomposition  of  2  grams  of  H^O? 

19.  How  much  O  would  be  required  to  oxidize  the  metallic  Cu  which 
could  be  reduced  from  its  oxide  by  passing  over  it,  when  white-hot,  20 
grams  of  H  gas? 

20.  How  much  O  would  be  required  to  oxidize  the  metallic  Pe  which 
could  be  reduced  in  the  same  manner  by  10  grams  of  H  gas? 

21.  WTiy  are  rose-balloons  so  buoyant? 

22.  How  much  H  must  be  burned  to  produce  a  ton  of  water? 


CARBON. 

Symbol,  C,     Atomic  Weight,  12,     Specific  Gravity  of  Diamond,  3.5  to  3.6. 

Occurrence. — C  is  one  of  the  most  abundant  sub- 
stances in  nature,  forming  nearly  one  half  of  the 
entire  vegetable  kingdom,  and  being  a  prominent 
constituent  of  lime-stone,  corals,  ixiarble,  magnesian 
rocks,  etc.  We  find  it  uncombined  in  two  distinct 
forms  or  allotropic  conditions — viz.,  the  diamond  and 
graphite. 

The  Diamond  is  pure  carbon  crystallized.  It  is 
the   hardest  of    all   known   substances,   scratches  all 


54  INORGANIC     CHEMISTRY. 

other  minerals  and  gems,  and  can  be  cut  only  by 
its  own  dust.  It  is  infusible,  but  will  burn  at  a  high 
temperature.  Nearly  all  the  diamonds  of  commerce 
now  come  from  the  Cape  of  Good  Hope.  India, 
Borneo,  and  Brazil  had  valuable  mines,  and  in  1858 
Brazil  furnished  120,000  carats.*  Diamonds  usually 
occur  crystallized  in  the  form  of  the  regular  octahe- 
dron or  forms  derived  from  it  belonging  to  the  reg- 
ular system  of  crystallography.  They  are  of  various 
tints,  though  often  colorless  and  perfectly  transparent. 
The  last  are  most  highly  esteemed  and,  from  their 
resemblance  to  a  drop  of  clear  spring-water,  are 
called  diamonds  of  the  "  first  water."  They  are  ex- 
ceedingly brittle,  and  valuable  gems  are  said  to  have 
been  broken  by  simply  falling  to  the  floor.  Nothing 
definite  is  known  concerning  the  origin  of  this  gem.f 


*  A  carat  is  a  little  less  than  4  grains  Troy.  The  term  is  derived  from 
the  name  of  a  bean,  which,  when  dried,  was  formerly  used  in  weighing  by 
the  diamond  merchants  in  India. 

t  Although  the  diamond  is  simply  pure  carbon  crj'stallized,  all  attempts 
to  make  it  have  been  until  recently  unsuccessful.  A  few  years  ago,  it  was 
discovered  that  artificial  diamonds  having  all  the  characteristics  of  the  nat- 
ural stones  could  be  formed  ;  but  thus  far,  all  that  have  been  made  are  verj' 
minute  and  interesting  only  from  a  scientific  point  of  view.  The  value  of 
the  diamond  varies  with  the  market;  the  aeneral  rule  is  as  follows:  a  gem 
ready  for  setting,  of  one  carat  weight,  is  worth  $150  to  $180 ;  licyond  this 
size,  the  estimated  value  increases  according  to  the  square  of  the  weight, 
but  in  case  of  large  stones  is  generally  much  less  than  that  amount, 
although  rare  beauty  or  size  may  greatly  enhance  the  price.  The  Kohi- 
noor  (mountain  of  light,  now  among  the  crown  jewels  of  England)  weighs 
103  carats,  yet  is  valued  at  ?10,000.000.  Owing  to  the  discovery  of  many 
large  diamonds  in  South  Africa,  the  value  of  such  stones  has  much  decreased 
of  late.  The  smaller  ones,  however,  are  becoming  more  expensive  on 
account  of  the  greater  demand  for  them.  The  South  African  diamonds  are 
seldom  colorless,  having  generally  a  yellowish  tint.  Paste  diamonds  are 
now  made  in  Paris,  which  are  so  perfect  an  imitation  that  only  experts 
can  distinguish  them  from  the  real  gems. 


CARBON.  OD 

The  Diamond  is  ground  by  means  of  its  own 
powder.  Being  fitted  to  the  end  of  a  stick  or  handle, 
it  is  pressed  down  firmly  against  the  face  of  a  rapidly 
revolving  wheel,  covered  with  diamond-dust  and  oil. 
This,  by  its  friction,  removes  the  exposed  edge  and 
forms  a  facet  of  the  gem.  There 
are   three    forms    of    cutting — the  ^'**-  ~~- 

brilHaiit,  the   ivse,  and  the   table. 
The  brilliant  has  a  flat  surface  on 

the    top,    with     facets     at    the    side,       The  MUiant.      The  rose. 

and  also  below,  the  latter  termi- 
nating in  a  point,  so  arranged  as  to  refract  the  light 
most  brillianth\  This  form  shows  the  gem  to  the 
best  advantage,  but  is  used  only  in  large,  thick 
stones,  as  it  sacrifices  nearly  half  the  weight  in  cut- 
ting. The  rose  is  fiat  beneath,  while  the  upper  sur- 
face is  ground  into  triangular  facets,  terminating  at 
a  common  vertex.  The  table  form  is  employed  for 
thin  specimens,  which  are  merely  ornamented  by 
small  facets  on  the  edge.  The  diamond  is  valued 
not  alone  for  its  rarity  and  high  refractive  power, 
by  which  it  flashes  such  vivid  and  brilliant  colors, 
but  also  for  its  mechanical  uses.  For  cutting  glass, 
the  curved  edges  of  the  natural  crystal  are  used. 

Graphite  or  Plumbago  is  also  called  black-lead, 
because  on  paper  it  makes  a  shining  mark  like  lead. 
It  is  found  at  Ticonderoga,  N.  Y.,  Brandon,  Vt., 
Sturbridge,  Mass.,  and  in  Germany,  South  Siberia, 
Ceylon,  and  Australia. 

Uses.— A  chief  use  is  for  pencils.  For  this  pur- 
pose a  mixture  of  powdered  graphite  and  carefully 


56  INOKGANIC     CHEMISTRY. 

washed  clay  is  employed.*  Though  graphite  seems 
very  soft,  yet  its  particles  are  extremely  hard  and 
the  saws  used  in  cutting  it  soon  wear  out.  We  no- 
tice this  property  in  sharpening  a  pencil  with  a 
knife.  Graphite  mixed  with  clay  is  made  into  black- 
lead  crucibles.  These  are  the  most  refractory  known 
and  are  used  for  melting  gold  and  silver.  It  is  also 
sold  as  "British  luster,"  "carburet  of  iron,"  "stove 
polish,"  etc.,  which  are  employed  for  blacking  stoves 
and  protecting  iron  from  rusting. 

Amorphous  Carbon. — This  name  is  given  to  all 
modifications  of  carbon  which  are  not  diamond  or 
graphite.  The  term  amorphous  means  without  crys- 
talline form.  Under  this  head  are  included  lamp- 
black, charcoal,  coke,  gas-carbon,  animal  charcoal, 
and  coal. 

Lamp-black  is  obtained  b}'  imperfectly  burning 
pitch  or  tar.  The  dense  cloud  of  smoke  is  conducted 
into  a  chamber  lined  with  sacking,  upon  which  the 
soot  collects.  It  is  largely  used  in  painting.  It  is 
mixed  with  clay  to  form  black  drawing  crayons,  and 
with  linseed  oil  to  make  printers'  ink.  Lamp-black 
has  peculiar  properties  which  fit  it  for  printing. 
Nothing  in  nature  could  supply  its  place.  No  mat- 
ter how  finely  it  is  pulverized,  it  retains  its  dead- 
black  color.  The  minutest  particle  is  as  black  as  the 
largest  mass.     It  is  insoluble   in  all  liquids.     It  never 

♦  The  graphite  and  claj'  are  mixed  with  water  to  a  semi-solid  mass, 
which  is  then  placed  in  a  short  iron  cylinder  having  a  small  opening  in  the 
bottom  and  forced  through  the  hole  by  pressure.  In  this  way  a  long 
plastic  thread  is  obtained,  which  is  cut  into  the  required  lengths  and 
heated. 


CARBON.  57 

decays.  The  paper  may  molder ;  we  may  even  burn 
it,  and  still,  in  the  ashes,  we  can  trace  the  form 
of  the  printed  letter.  The  ancients  used  an  ink 
composed  of  gum-water  and  lamp-black,  and  manu- 
scripts have  been  exhumed  from  the  ruins  of  Pompeii 
and  Herculaneum  which  are  yet  perfectly  legible. 

Soot  is  unburnt  carbon  which  passes  off  from  a 
lamp  or  fire  when  there  is  not  enough  0  present  to 
combine  with  all  the  C  of  the  fuel.  This,  therefore, 
comes  away  in  flakes,  and  blackens  the  chimney  of 
the  lamp  or  lodges  in  the  chimney  of  the  house. 
After  a  time,  a  large  quantity  having  collected,  we 
are  startled  by  the  cry,  "  The  chimney  is  on  fire  ! " 
while  with  a  great  roar  and  flame  the  soot  burns 
out.  This  unpleasant  occurrence  is  much  more  fre- 
quent when  green  wood  is  used  for  fuel.  The  HgO 
of  the  wood  absorbs  much  of  the  heat  of  the  fire, 
and  so  permits  the  C  to  pass  off  unconsumed. 

Charcoal  is  made  by  burning  piles  of  wood,  so 
covered  over  with  turf  as  to  prevent  free  access  of 
air.  The  volatile  gases,  water,  etc.,  are  driven  off 
and  the  C  left  behind.  This  forms  about  |  of  the 
bulk  of  the  wood  and  \  its  weight.  Charcoal  for 
gunpowder  and  for  medicinal  purposes  is  prepared 
by  heating  Avillow  or  poplar  wood  in  iron  retorts. 

Coke  is  obtained  by  distilling  the  water,  tar,  and 
volatile  gases  from  bituminous  coal.  It  is  burned  in 
locomotives,  blast-furnaces,  etc. 

Gas-carbon  is  formed  on  the  interior  of  the  re- 
torts used  in  coal-gas  works.  It  has  a  metallic  luster, 
and  will  scratch  glass. 


INORGANIC     CHEMISTRY. 
Fio.   23. 


Making  charcoal. 

Animal  Charcoal^  or  bone-black,  is  made  by  heat- 
ing bones  in  close  vessels.  Mixed  with  H2SO4,  it 
forms  the  basis  of  paste-blacking.  It  is  largely  used 
by  sugar-refiners  (p.  217).  Common  vinegar  filtered 
through  it  becomes  the  white  vinegar  of  the  pickle 
manufacturers. 

Mineral  Coal. — This  was  formed  at  an  earl}-  period 
of  the  world's  history,  called  the  Carboniferous  Age. 
The  earth's  surface  was  then  pervaded  by  a  genial 
tropical  climate.  The  air  was  denser  and  richer  with 
vegetable  food  than  now.  The  surface  itself  was  a 
swamp,  moist  and  hot,  in  which  simple  ferns  towered 
into  trunks  a  foot  and  a  half  in  diameter ;  and  where 
plants  like  those  which  creep  at  our  feet  to-day,  or 


CARBON.  59 

are  known  only  as  rushes  or  grasses,  grew  to  the 
height  of  lofty  trees.  The  song  of  bird  or  hum  of 
insect  rarely  echoed  through  the  mighty  fern-forests  ; 
but  a  strange  and  grotesque  vegetation  flourished 
with  more  than  tropical  luxuriance.  In  these  swamps 
accumulated  a  vast  deposit  of  leaves  and  fallen 
trunks  which,  under  the  water,  was  gradually  de- 
composed. In  the  process  of  time  the  earth  settled 
at  various  points  and  floods  poured  in,  bringing 
sand,  pebbles,  clay,  and  mud,  filling  up  all  the  spaces 
between  the  trees  that  were  standing  and  even  the 
hollow  trunks  themselves.  The  pressure  of  this  soil 
and  possibly  the  internal  heat  of  the  earth  combined 
to  expel  the  gases  from  the  vegetable  deposits  and 
convert  these  into  mineral  coal.*  In  time,  this  section 
was  elevated  again  and  another  forest  flourished,  to  be 
in  its  turn  converted  into  coal.  Each  of  these  alter- 
nate elevations  and  depressions  produced  a  layer  of 
coal  or  of  soil.  In  these  beds  of  coal  we  now  find 
the  trunks  of  trees,  the  outlines  of  trailing  vines,  the 
stems  and  leaves  of  plants  as  perfectly  preserved  as 
in  a  herbarium,  so  that  the  flora  of  the  Carbonifer- 
ous Age  is  nearly  as  complete  as  that  of  our  own. 

Peat  is  an  accumulation  of  half  decomposed  veg- 
etable   matter    in    swampy   places. f     It    is   produced 

*  Where  this  process  was  nearly  complete,  anthracite  coal,  and  where 
only  partially  finished,  bituminous  coal,  was  formed.  The  gi-eater  the 
pressure,  the  harder  and  purer  the  carbon  produced ;  unless,  however,  the 
covering  was  not  sufficiently  porous  to  allow  the  gases  to  escape,  when 
bituminous  coal  was  the  result. 

t  These  peat-beds  are  of  vast  extent.  One  tenth  of  Ireland  is  covered 
by  them.  A  bed  near  the  mouth  of  the  River  Loire,  is  said  to  be  fifty 
leagues  in  ciroumference. 


60  INORGANIC     CHEMISTKY. 

mainly  by  a  kind  of  moss  which  gradually  dies  be- 
low as  it  grows  above  and  thus  forms  beds  of  great 
thickness.  Sometimes,  however,  plants  may  grow 
in  the  form  of  a  turf  and  decay,  thus  collecting  a 
vast  amount  of  vegetable  debris.  This  gradually  un- 
dergoes a  change  and  becomes  a  brownish  black 
substance,  loose  and  friable  in  its  texture,  resembling 
coal,  but,  unlike  it,  containing  20  to  30  per  cent, 
of  0.  Peat  is  used  in  large  quantities  as  a  fuel. 
For  this  purpose,  it  is  cut  out  in  square  blocks 
and  dried  in  the  sun.  In  some  beds  it  is  first  finely 
pulverized,  then  pressed  into  a  very  compact  form 
like  brick. 

Muck  is  an  impure  kind  of  peat,  not  so  fully  car- 
bonized ;  though  the  term  is  frequently  applied  to 
any  black  swampy  soil  which  contains  a  large  quan- 
tity of  decaying  vegetable  matter.  It  is  used  as  a 
fertilizer. 

Various  Forms  and  Uses  of  Carbon. — We  have 
seen  in  what  contrary  forms  C  presents  itself.  It  is 
soft  enough  for  the  pencil-sketch  and  hard  enough 
for  the  glazier's  use.  Black  and  opaque,  it  expresses 
thought  on  the  printed  page  ;  clear  and  brilliant,  it 
gleams  and  flashes  in  the  diadem  of  a  king.  Lamp- 
black and  charcoal  are  readily  kindled ;  graphite 
resists  the  heat  of  the  fiercest  flame.  In  the  dia- 
mond, carbon  is  an  insulator ;  while  in  the  form 
of  gas-carbon,  it  is  a  conductor  of  electricity,  and 
is  used  in  electrical  batteries  and  in  the  arc  light. 
In  our  lamps  it  gives  us  light ;  we  burn  it  in 
our   stoves    and    it   gives  us   heat ;    we   burn    it  in 


CARBON.  bl 

our  engines  and  it  gives  us  power ;  we  burn  it  in 
our  bodies  and  it  gives  us  strength.  As  fuel,  it 
readily  unites  with  0,  yet  we  spread  it  as  stove- 
polish  on  our  iron-ware  to  keep  the  metal  from  rust- 
ing. It  gives  firmness  to  the  tree  and  consistency  to 
our  flesh.  It  is  the  valuable  element  of  all  fuel, 
burning  oils,  and  gases.  Thus  it  supplies  our  wants 
in  the  most  diverse  manner,  illustrating  in  every 
phase  the  forethought  of  that  Being  who  fitted  up 
this  world  as  a  home  for  His  children.  Infinite  Wis- 
dom alone  would  have  stored  up  such  supplies  of 
fuel  and  light  and  hidden  them  far  under  the  earth 
away  from  all  danger  of  accidental  combustion,  or 
anticipated  the  requirements  alike  of  luxury  and 
the  arts. 

Properties  of  Carbon. — Each  of  these  various  sub- 
stances possesses  different  properties,  and  yet  all 
have  certain  properties  in  common  which  prove 
them  to  consist  of  one  and  the  same  element.  They 
are  all  tasteless  and  without  color.  They  are  all 
infusible,  and  all  of  them,  when  heated  in  air  or  0, 
unite  Avith  the  same  proportion  of  0,  forming  pre- 
cisely the  same  compound  —  carbon  dioxide — from 
which  the  C  can  be  obtained  again  in  the  form  of 
charcoal.  Carbon  is  the  most  unchangeable  of  all 
the  elements,  so  that  even  in  the  charcoal  we  can 
trace  all  the  delicate  structure  of  the  plant  from 
which  it  was  made.  Neither  air  nor  moisture  affects 
it.  Wheat  has  been  found  in  the  ruins  of  Hercu- 
laneum  that  was  charred  1800  years  ago,  and  yet 
the  kernels  are  as  perfect  as  if  grown  last  harvest. 


62  INORGANIC     CHEMISTRY, 

The  ground  ends  of  posts  are  rendered  durable  by 
charring.  Indeed,  some  were  dug  up  not  long  since 
in  the  bed  of  the  Thames  whi(,'h  were  placed  there 
by  the  ancient  Britons  to  oppose  the  passage  of 
Julius  Caesar  and  his  army.  A  cubic  inch  of  fine 
charcoal  has,  it  is  said,  100  feet  of  surface,  so  full 
is  it  of  minute  pores.  These  absorb  and  condense 
gases  to  an  almost  incredible  extent.  A  bit  of  C 
will  take  up  ninety  times  its  bulk  of  ammonia.  As 
the  various  gases  and  the  0  of  the  air  are  brought 
so  closely  together  within  its  pores,  rapid  oxidation 
is  produced,  as  in  the  case  of  spongy  platinum  (see 
p.  42).  Pans  of  charcoal  soon  purify  the  offensive 
air  of  a  hospital.  Foul  water  filtered  through  C 
loses  its  impurities.  Beer  by  this  process  parts  not 
only  with  its  color,  but  with  its  bitter  taste.  Ink 
is  robbed  of  its  value,  and  comes  out  clear  and 
transparent  as  water. 

Deoxidizing  or  Reducing  Action  of  C. — At  a  high 
temperature  the  attraction  of  C  for  0  is  powerful. 
In  the  heat  of  a  furnace  it  will  take  it  from  almost 
the  stablest  compounds.  This  fact  gives  to  char- 
coal great  value  in  the  arts.  Nearly  all  the  metals 
and  many  of  the  other  elements  are  locked  up  in 
the  rocks  with  0,  and  C  is  the  key  made  by  the 
Creator  for  unlocking  the  treasure-houses  of  nature 
for  the  supply  of  our  wants.  By  noticing  the  process 
of  preparing  zinc,  iron,  phosphorus,  etc.,  we  shall 
see  the  importance  of  this  property  of  C.  A  very 
.pretty  illustration  is  shown  by  placing  a  few  grains 
of  litharge    (PbO)    on   a  flat   piece    of   charcoal,   and 


CARBON.  63 

directing   upon    it    the    flame    of    a   blow-pipe.     The 
metal    will    immediately    appear    in 
little  sparkling  globules. 

Compounds.  —  Carbon  Dioxide, 
COg. — Occurrence. — This  gas  is  com- 
monly known  as  Carbonic  Acid.  It  p^^  ^,^  ^^^,,^.,^^ 
is  found  combined  with  lime  in  a 
large  class  of  salts,  known  as  the  carbonates,  viz., 
limestone,  marble,  chalk,  etc.,  forming  nearly  one 
half  of  their  weight,  and  almost  one  seventh  of 
the  crust  of  the  earth.  It  comprises  ttooit  of  the 
atmosphere.  It  is  produced  throughout  nature  in 
immense  quantities.  Wherever  C  burns,  in  fires, 
lights,  decay,  volcanoes — in  a  word,  in  all  those  va- 
rious forms  of  combustion  of  which  we  spoke  under 
the  subject  of  0,  where  that  gas  unites  with  C,  CO2 
is  the  result.  Each  adult  exhales  daily  about  SJ  oz. 
of  carbon  changed  to  this  invisible  gas.  Each  bushel 
of  charcoal,  in  burning,  produces  not  far  from  2500 
gallons.  A  lighted  candle  gives  off  a])out  four  gal- 
lons per  hour. 

Preparation.  —  For  experimental  purposes,  CO2  is 
prepared  by  pouring  hydrochloric  (muriatic)  acid  on 
marble  or  chalk.  The  reaction  may  be  represented 
as  follows : 

CaCOs  +  2HC1  =  Cads  +  HjO  +  CO2. 

The  CO2  is  liberated  rapidly  and,  as  it  is  much 
heavier  than  air,  may  be  collected  by  downward  dis- 
placement (see  Fig.  25),  while  the  calcium  chloride 
remains  dissolved  in  the  water  of  the  flask. 


6-i 


INORGANIC     CHEMISTRY. 


The  test  for  CO 2  is  clear  lime-water.  If  we  ex- 
pose a  saucer  of  lime-water  to  the  air,  the  surface 
of  the    solution   will    soon    be    covered   with    a   thin 


Fig.   25. 


Preparing  COj.'' 

film  of  calcium  carbonate  (carbonate  of  lime),  thus 
showing  that  there  is  CO 2  in  the  atmosphere ;  or 
if  we  breathe  by  means  of  a  tube  through  lime- 
w^ater,  the  solution  will  l)ecome  turbid  and  milky, 
thus  proving  the  pre.sence  of  CO2  in  our  breath;  by 
breathing  through  the  liquid  a  little  longer  it  will 
become  cloai-,  as  the  carbonate  will  dissolve  in  an 
excess  of  CO 2-1 

*  Twist  a  wiro  around  the  neck  of  a  small,  wide-mouthed  vial,  to  serve 
as  a  hucket.  Dip  the  COa  with  it  upicard  from  the  jar  and  test  with  a 
lighted  match.  Dip  the  H  (Fig.  15)  dotvnward,  and  test  in  same  way.  This 
illustrates  in  a  striking  manner  the  difference  between  the  gases  in  respect 
to  specific  gi-avity  and  combustion. 

+  Burn  a  piece  of  charcoal  oi-  a  candle  in  a  jar  of  O.  Pour  in  a  little 
lime-water  and  shake  it  well,  when  there  will  be  a  jirecipit-ation  of  chalk 
(calcium  carbonate).  Hold  a  jar  of  air  over  a  burning  lamp  or  jet  of  coal- 
gas,  or  Ijroathc  into  the  jar  and  apply  the  test. 


CARBON. 


65 


Properties. —  CO2  is  a  colorless,  odorless,  trans- 
parent gas,  with  a  slightly  acid  taste,  and  is  a  non- 
supporter  of  combustion.  Since  it  is  heavier  than 
air,    many   amusing   experiments    can   be    performed 


Fig.   36. 


Ponnng  COa  doicn   a.i   i/idi/ud  plane. 

with  it.  It  will  run  down  an  inclined  plane,  can 
be  poured  from  one  dish  to  another,  drawn  off  bv 
a  siphon,  dipped  up  with  a  bucket  like  water,  or 
weighed  in  a  pair  of  scales  like  lead. 

To  show  the  C  in  CO2,  hold  a  strip  of  Mg  foil 
in  a  flame  until  well  ignited,  then  insert  in  a  jar 
of  the  gas.  ^Vliite  flakes  of  magnesium  oxide* 
(MgO)  mixed  with  black  particles  of  charcoal  will  be 
deposited. 

*  These  may  be  dissolved  by  dilute  HNC),,  and  the  black  C  made  more 
distinct. 


06 


INORGANIC     CHEMISTRY. 
Fig.  27. 


Fig.   28. 


Weighing  CO  2. 

Asphyxia. — CO2  accumulates  in  old  wells  and  cel- 
lars, where  it  has  cost  the  lives  of  many  incautious 
persons.*  The  test  of  lowering  a  lighted  candle  should 
always  be  employed.  If  that  be  extinguished,  your 
life  would  be  in  danger  of  "  going  out " 
in  the  same  way,  should  you  descend. 
The  gas  may  be  dipped  out  like  water, 
or  the  well  may  be  purified  by  lowering 
pans  of  slaked  lime  or  lighted  coals 
\vhich,  when  cool,  will  absorb  the  nox- 
ious gas.  The  coals  may  be  re-ignited, 
and  lowered  repeatedly  until  the  result 
is  reached. f  Persons  have  been  suffo- 
cated by  burning  charcoal  in  an  open 
furnace  in  a  closed  room.].  In  France, 
suicide  is  sometim.es  committed  in  this  manner.     The 

*  "Three  cr  four  per  cent,  of  COj  in  the  air  acts  ;.;;  a  narcotic  poieon 
by  preventing  the  proper  action  of  the  air  uiwn  the  blood."— Miller. 

+  A  well  in  which  a  candle  would  not  burn  within  twenty-six  feet  of 
the  bottom,  was  thus  purified  in  a  single  afternoon. 

i  The  fumes  of  burning  charcoal  owe  their  deadly  property  largely  to 
the  presence  of  CO  (page  70),  one  per  cent,  of  wliieh  in  the  air  causes 
headache. 


Poiniiig   CO3  on   a 
light. 


CARBON".  67 

antidote  is  to  bring  the  sufferer  into  the  fresh  air 
and  dash  cold  water  upon  his  face.  In  the  cele- 
brated Grotto  del  Cane,  near  Naples,  the  gas  accu- 
mulates upon  the  floor,  so  that  a  man  living  near 
amuses  visitors,  for  a  small  fee,  by  leading  his  dog 
into  the  cave.  He  experiences  no  ill  effects  himself, 
but  the  dog  falls  senseless.  On  being  drawn  into 
the  open  air,  the  animal  soon  revives,  and  is  ready 
to  pick  up  his  bit  of  black  bread  and  enjoy  this  re- 
ward for  his  demonstration  of  the  properties  of  CO 2. 
CO2  in  Mines. — Miners  call  CO2  clioke-damp.  It  is 
produced  by  the  combustion  oi  fire-damp  (see  p.  71), 
which  accumulates  in  deep  mines,*  and  when  mixed 
with  air,  explodes  like  gunpowder,  forming  dense  vol- 
umes of  CO2,  which  instantly  destroys  the  lives  of 
all  who  may  have  escaped  the  flames  of  the  explo- 
sion, f  CO 2  has  been  used  for  the  purpose  of  extin- 
guishing fires  in  coal-mines.  A  mine  near  Sterling, 
England,  had  burned  for  tliirty  years,  consuming  a, 

*  The  word  gas  was  first  used  in  the  seventeenth  century.  Explosions, 
strange  noises  and  lurid  flames  had  been  seen  in  mir.es,  caves,  etc.  The 
alchemists,  whose  earthen  vessels  often  exploded  with  terrific  violence, 
commenced  their  experiments  with  prayer  and  placed  on  their  crucibles 
the  sign  of  the  cross— hence  the  name  crucible  from  crux  (gen.  crucis),  a 
cross.  All  these  manifestations  were  supposed  to  be  the  work  of  invisible 
spirits,  to  whom  the  name  rast  or  geist,  a  ghost  or  spirit,  was  applied.  The 
miners  were  in  special  danger  from  these  unseen  adversaries,  and  it  is  said 
that  their  church  service  contained  the  petition,  "From  spirits,  good  Lord, 
deliver  us!"  The  names  "spirits  of  wine,"  "spirits  of  niter,"  etc.,  are  a 
relic  of  the  superstitions  of  that  time. 

t  "Where  CO 3  alone  is  found,  it  is  not  considered  as  dangerous  as  the 
fire-damp,  since  it  will  not  burn ;  and  it  is  said  that  miners  will  even  venture 
"  where  the  air  is  so  foul  that  the  candles  go  out,  and  are  then  re-lighted 
from  the  coal  on  the  wick  by  swinging  them  quickly  through  the  air, 
when  they  burn  a  little  while  and  then  go  out,  and  are  re-lighted  in  the 
same  way." 


68  INORGANIC     CHEMISTRY. 

seam  of  coal  nine  feet  thick,  over  an  area  of  twenty- 
six  acres.  CO2,  eight  niiUion  cubic  feet  of  which 
were  required,  was  poured  into  the  mine,  in  a  con- 
tinuous stream,  day  and  night,  for  three  weeks.  The 
mine  was  then  cooled  with  water,  and  within  a 
month  from  the  commencement  of  the  operation, 
was  ready  for  the  resumption  of  work. 

Absorption  of  CO2  by  Liquids. — Water  dissolves 
its  own  volume  of  CO2  under  the  ordinary  pressure 
of  the  atmosphere,  forming  a  solution  of  carbonic 
acid;  CO2  +  H2O  becoming  H2CO3.  "With  increased 
pressure  a  much  greater  amount  will  be  absorbed. 
"Soda  water"  contains  no  soda,  but  is  simply  H2O 
saturated  with  CO 2  in  a  copper  receiver  strong 
enough  to  resist  the  pressure  of  ten  or  twelve  atmos- 
pheres. The  gas  gives  the  H2O  a  pleasant,  pungent, 
slightly  acid  taste,  and  by  its  escape,  when  exposed 
to  the  air,  produces  a  brisk  effervescence.*  In  beer, 
ginger-pop,  cider,  wine,  etc.,  the  CO 2  is  produced  by 
fermentation.!  The  gas  escapes  rapidly  through  cider 
and  wine,  and  so  produces  only  a  sparkling ;  while 
in  a  thick,  viscid  liquid,  like  beer,  the  bubbles  are 
partly  confined,  and  hence  cause  it  to  foam  and 
froth.  In  canned  fruits,  catsup,  etc.,  the  "  souring  "  of 
the  vegetables  produces  COj,  which  sometimes  drives 
OU.I  the  cork  or  bursts  the  l)ottles  Avith  a  loud  report. 

*  Pass  a  current  of  CO,  through  a  gill  of  water.  Add  a  few  drops  of 
blue  litmus-solution.  It  will  immediately  redden.  Boil  the  water,  when 
the  gas  will  escape  and  the  water  become  blue. 

t  Dissolve  an  ounce  of  sugar  in  ton  times  its  weight  of  water.  Put  it 
in  a  flask  and  add  a  little  fresh  brewer's  yeast.  If  kept  warm,  in  a  short 
time  it  will  give  off  CO,,  which  may  be  tested. 


CARBON.  69 

Liquid  CO 2. — B}^  a  pressure  of  thirty-six  atmos- 
pheres, at  a  temperature  of  32''F.,  CO2  becomes  a 
colorless  liquid  very  much  lilce  HgO.  When  this  is 
exposed  to  the  air,  it  evaporates  so  rapidly  that  a 
portion  is  frozen  into  a  snowy  solid  which  blisters  the 
flesh  like  red-hot  iron.  By  means  of  solid  CO2,  Hg 
can  be  readily  frozen.  When  mixed  with  ether  and 
evaporated  under  the  exhausted  receiver  of  an  air- 
pump,  a  cold  of  —  110°C.  may  be  produced.  (See 
"Physics,"  p.  191.) 

Ventilation. — The  relation  of  CO 2  to  life  is  iTiost 
important,  and  can  not  be  too  often  dwelt  upon. 
We  exhale  constantly  this  dangerous  gas,  and  if  fresh 
air  is  not  furnished  continuously,  we  are  forced  to 
rebreathe  that  which  our  lungs  have  just 'expelled.* 
The  languor  and  sleepiness  we  feel  in  a  crowded 
assembly,  are  the  natural  effects  of  the  vitiated 
atmosphere. t  The  idea  of  drinking  in  at  every 
breath  the  exhalations  that  load  the  air  of  a  crowded, 
promiscuous  assembly-room,  is  a  most  disgusting 
one.  We  shun  impurity  in  every  form  ;  we  dislike 
to  wear  the  clothes  of  another,  or  to  eat  from  the 
same  dish  ;  we  shrink  from  contact  with  the  filthy, 
and  yet  sitting   in   the   same   room   inhale   their  pol- 

*  It  is  a  fact,  as  poetical  as  it  is  characteristic,  that  when  the  air  comes 
forth  from  the  lungs,  it  is  charged  with  the  seeds  of  disease ;  yet,  as  it 
passes  out,  it  produces  all  the  tones  of  the  hu^man  voice,  all  songs,  and 
prayers,  and  social  converse.  Thus  the  gross  and  deadly  is,  by  a  divine 
simplicity,  made  refined  and  spiritual,  and  caused  to  minister  to  our  highest 
happiness  and  welfare. 

t  It  should  be  noted  that  the  deleterious  effects  of  ill  ventilation  arise 
not  only  from  the  presence  of  CO„,  but  from  the  organic  particles  given  off 
in  the  breath  and  exhaled  from  the  skin.  (See  "Physiology,"  p.  93,)  Ee- 
breathed  air  is  a  fruitful  source  of  consumption  and  scrofula. 


70  INORGANIC     CHEMISTRY. 

Fig.  29. 


Tenting  the  currents  of  air  to  and  from  flame. 

luted  breath.  Health  and  cleanliness  alike  require 
that  we  should  carefully  ventilate  public  buildings, 
school-rooms  and  sleeping  apartments,* 

Carbon  Monoxide,  CO,  is  a  colorless,  almost  odor- 
less gas    nearly  insoluble   in  water.     It  burns  with  a 

*  Two  openings  are  necessary  to  ventilate  a  room.  To  illiistrate  this, 
set  a  lighted  candle  in  a  plate  of  water,  as  shown  in  Fig.  29.  Cover  it  with 
an  open  jar,  over  the  neck  of  which  is  placed  a  common  lamp-chimney. 
The  light  will  soon  be  extinguished  on  account  of  the  consumption  of  O, 
and  the  formation  of  COi.  Eaise  the  jar  at  one  side  a  trifle  above  the 
water,  and  the  candle,  if  re-lightcd,  will  burn  steadily— fresh  air  coming  in 
below,  and  the  refuse  passing  off  at  the  top.  Replace  the  jar,  and  as  the 
candle  is  flickering,  insert  in  the  chimney  a  slip  of  card,  thus  dividing  the 
passage,  when  the  light  will  brighten  again.  Hold  a  bit  of  smoldering 
touch-paper  (page  32)  at  the  top,  and  the  smoke  will  show  two  opposite 
currents  of  air  established  in  the  chimney.  Mines  have  been  ventilated  in 
this  way  by  dividing  the  shaft.  More  commonly,  however,  they  have  two 
shafts  at  a  little  distance  apart. 


CARBON,  71 

pale  blue  flame,  absorbing  an  atom  of  0  from  the 
air  and  becoming  CO 3.  It  is  seen  burning  thus 
in  our  coal-stoves  and  at  the  tops  of  tall  furnace- 
chimneys.  It  is  often  formed  abundantly  through 
the  action  of  heated  carbon  on  COj.  When  air 
enters  at  the  bottom  of  a  clear  fire,  CO 2  is  formed 
at  once  ;  but  this  gas  passing  through  the  hot  em- 
bers takes  up  a  further  quantity  of  C,  becoming 
changed  into  CO:*  C  +  CO2  =  2 CO,  the  volume  of 
the  gas  being  exactly  doubled  in  bulk  thereby.  CO 
is  a  deadly  poison,  and  escaping  from  coal-fires  in  a 
close  room,  has  often  produced  death.  Both  CO  and 
CO2  leak  through  the  pores  of  cast  Fe  when  heated, 
and  still  further  injure  the  air  of  our  houses  and 
necessitate  ventilation.  The  offensive  odor  which 
comes  out  on  opening  the 
door  of  our  coal-stoves 
is  caused  by  the  com- 
pounds of  S  mixed  with 
the  CO. 

Marsh-Gas. — Light  Car-     —  la^ 

huretted    Hydrogen^    CH^.. 
—  This    we    have    already 

spoken   of  under   CO2,  as  ^^^^^^.^^^  Marsh-ga.. 

the  dreaded  fire-damp   of 

miners.  It  is  colorless,  tasteless,  odorless,  and  burns 
with  a  pale  yellowish  flame.  It  is  formed  in  swamps 
and    low    marshy    places    by    the    decomposition    of 


*  This  fact  is  of  great  importance,  since  thereby  much  heat  is  wasted, 
stoves  are  often  so  constructed  as  to  admit  fresh  air  just  above  the  grate, 
thus  consuming  this  gas. 


72  INORGANIC     CHEMISTRY. 

vegetable  matter,  and  on  stirring  the  mud  beneath, 
will  be  seen  bubbling  up  through  the  water.  It  may 
be  collected  in  the  manner  shown  in  Fig.  30.  It 
rises  from  the  earth  in  great  quantities  at  many- 
places.  At  Fredonia,  N.  Y.,  it  is  used  in  lighting  the 
village.  At  Kanawha,  Va.,  it  was,  until  lately,  em- 
ployed as  fuel  for  evaporating  the  brine  in  the 
manufacture  of  salt.  In  the  oil-wells  of  Pennsyl- 
vania, it  frequently  bursts  forth  with  explosive  vio- 
lence, throwing  the  oil  high  into  the  air. 

Olefiant  Gas. — Heavy  Carhuretted  Hydrogen,  CgH^.. 
— This  is  a  colorless  gas,  with  a  sweet,  pleasant  odor, 
and  burns  with  a  clear  white  light.'''  It  may  bo 
easily  prepared  by  heating  in  a  large  retort  a  mixt- 
ure of  one  part  of  alcohol  with  six  of  H0SO4. 

Coal-Gas  is  a  variable  mixture  of  combustible 
gases  and  vapors,  which  may  be  divided  into  two 
classes  :  1st.  The  illuminating  constituents,  olefiant 
gas  being  the  most  important ;  and  2d.  The  diluents, 
chiefly  H,  CO,  and  CH4.  Olefiant  gas  and  hydrocar- 
bons having  a  similar  composition,  give  whiteness  to 
the  flame;  while  the  H,  CH^,  and  CO  have  little 
illuminating  power.  Bituminous  coal  is  heated  in 
,largo  iron  retorts,  B,  until  the  volatile  constituents  are 
driven  off  and  only  coke  is  left.  Among  the  former 
are  coal-tar,  NH3,  COg,  CO,  N,  compounds  of  S,  CH4, 
and  C2H4.f     This  mixture   is  led  through  the  curved 

*  A  very  characteristic  property  of  olefiant  gas  is  its  power  of  uniting 
directly  with  an  equal  volume  of  01  to  form  a  heavy  oily  liquid  called 
Dutch  liquid.    It  is  to  this  that  it  owes  its  name  of  olefiant  gas. 

+  None  of  these  substances  exist  in  coal.  They  are  formed  by  the 
action  of  heat,  which  causes  the  H,  0,  O,  N,  and  S  to  combine  and  make 
a  multiplicity  of  compounds. 


CARBON. 


7B 


pipes,  d,  beneath  the  HgO 
in  the  hydraulic  main, 
F;  along  the  tune,  g,  to 
the  tar  cistern ;  thence 
np  and  down  the  con- 
denser, j.  On  ihe  way  it 
becomes  cooled  and  loses 
its  coal-tar,  ammoniacal 
salts,*  and  liquid  hydro- 
carbons. Lastly,  it  is 
passed  over  lime,  L  m, 
which  absorbs  the  CO 2 
and  the  H2S.f  The  re- 
maining gases  form  the 
mixture  we  call  "gas." 
This  is  collected  in  the 
gasometer,  P,  the  weight 
of  which  forces  it  through 
all  the  little  gas-pipes, 
and  up  to  every  jet  in 
the  city. 

Coal-gas  is  very  poison- 

*  The  NHs  is  neutralized  by  HCl, 
tlms  forming  chloride  of  ammonium 
(sal-ammoniac,  NH.Cl).  On  evapo- 
ration and  sublimation,  the  tough, 
fibrous  crystals  of  the  salt  are  ob- 
tained. 

t  The  removal  of  the  sulphur 
compounds  is  especially  important, 
since,  when  burned,  they  furnish 
aulphiirous  and  sulphuric  acids. 
These  acids  would  cause  very  great 
injury  to  books,  paintings,  and  fur- 
niture. 


Fig.  31. 


Manufacture  of  Coal-gas, 


74  INORGANIC     CHEMISTRY. 

ous,  and  even  in  small  quantities  exceedingly  delete- 
rious. When  mixed  with  air,  it  explodes  with  great 
violence.  Its  unpleasant  odor,  though  often  annoy- 
ing, is  a  great  protection,  as  we  are  thereby  warned 
of  its  presence. 

Water-Gas. — This  gas,  which  is  now  extensively 
used  both  for  heating  and  illuminating  purposes,  is 
made  by  leading  steam  over  red-hot  coke.  The  steam 
(H2O)  is  decomposed  by  the  C  of  the  coal  with  the 
production  of  H  and   CO,  as   shown   in   the  following 

equation  : 

C  +  H2O  ==  CO  +  2H. 

Both  H  and  CO  are  gases,  and  burn  with  great  heat ; 
when  passed  through  petroleum  oils,  they  become 
"  carburetted "  and  burn  with  a  luminous  flame. 

Cyanogen,*  Cy  =  CN. — Preparation. — As  N  and  C 
do  not  combine  directly,  this  gas  is  obtained  in  an 
indirect  way.  Mix  the  parings  of  horns,  hides,  etc., 
with  pearlash  (potassium  carbonate)  and  iron  filings, 
and  heat  in  a  close  vessel.  The  N  and  C  of  the 
animal  substances,  in  their  nascent  state,  will  com- 
bine, forming  Cy ;  this,  uniting  with  the  Fe  and  K, 
will  produce  potassium  ferro-cyanide  (yellow  prussiate 
of  potash),  a  solution  of  which  yields  fine  yellow 
crystals.  From  this  salt  mercury  cyanide  is  made, 
which,  when  heated,  decomposes  into  Hg  and  Cy. 

Properties. — Cy  is  a  transparent,  colorless  gas,  with 
a  p(!netrating  odor.  It  burns  with  a  characteristic 
rose-edged  purple  flame  and  is  exceedingly  poisonous, 

*  The  term  cyanogen  means  "  blue  producer  " ;  this  gas  being  the  chai-- 
acteristic  constituent  of  Prussian  blue. 


COMBUSTION.  75 

It  is  very  interesting  from  the  fact  that,  though  a 
compound,  it  unites  directly  with  the  metals  like 
the  elements  CI,  Br,  etc.  It  is  therefore  called  a 
compound  radical  (root).  We  shall  find  this  subject 
of  great  importance  in  Organic  Chemistry. 

Hydrocyanic  Acid,  HCy. — Prussic  acid,  as  it  is  com- 
monly called,  is  a  fearful  poison.  A  single  drop  on 
the  tongue  of  a  large  dog  is  said  to  produce  instant 
death.  NH3,  cautiously  inhaled,  is  its  antidote.  Its 
bitter  flavor  is  detected  in  peach  blossoms,  the  ker- 
nels of  plums  or  peaches,  bitter  almonds,  and  the 
leaves  of  wild  cherry. 

Fulminic  Acid  {fulmen,  a  thunder-bolt). — This  com- 
pound of  Cy  is  known  only  as  combined  with  the 
^^arious  metals  forming  fulminates,  which  are  remark- 
ably explosive.  Fulminating  mercury  was  used  to  fill 
the  bombs  with  which  the  life  of  Napoleon  III.  was 
attempted  in  1858.  It  is  employed  in  making  gun- 
caps.  A  drop  of  gum  is  first  put  in  the  bottom  of  the 
cap,  over  which  is  sprinkled  a  mixture  of  saltpeter,  sul- 
phur, and  fulminating  mercury,  and  this  is  sometimes 
covered  with  varnish  to  protect  it  from  any  moisture. 


COMBUSTION. 

Combustion,  in  general,  is  the  rapid  union  of  a 
substance  with  0,  and  is  accompanied  by  heat  and 
light.* 

Chemistry  of  a  Fire. — Our   fuel   and   lights,   such 

*  There  are  forms  of  combustion  known  to  the  chemist  which  are  not 
oxidation;  as  the  uuipn  of  S  and  Cu.    (See  page  87,  note.) 


76  INORGANIC     CHEMISTRY. 

as  wood,  coal,  oil,  tallow,  etc.,  consist  mainly  of  C 
and  H,  and  are,  therefore,  called  hydrocarbons.  In 
burning  they  unite  with  the  0  of  the  air,  forming 
HgO  and  CO2.  These  both  pass  off,  the  one  as  a 
vapor,  the  other  as  a  gas.  In  a  long  stove-pipe,  the 
H2O  is  sometimes  condensed,  and  drips  down,  bringing 
soot  upon  our  carpets.  Ashes  comprise  the  mineral 
matter  contained  in  the  fuel,  united  with  some  of 
the  CO2  produced  in  the  fire.  "\Yhen  we  first  put 
fuel  on  a  fire,  the  H  is  liberated  in  combination  with 
some  C,  in  the  form  of  marsh  or  olefiant  gas.  This 
burns  with  a  flame.  Then,  the  volatile  gases  having 
passed  off,  we  have  left  the  C,  which  burns  without 
flame.  In  maple  there  is  much  more  C  than  in  pine, 
so  it  forms  a  good  "bed  of  coals."  In  the  burning 
of  fuel  there  is  no  annihilation;  but  the  HjO,  CO2, 
and  the  ashes,  weigh  as  much  as  the  wood  and  the 
0  that  combined  with  it.  No  matter  how  rapidly 
the  fire  burns,  even  in  the  blaze  of  the  fiercest 
conflagration,  the  elements  unite  in  exact  atomic 
proportions. 

C  is  most  admirably  fitted  for  fuel,  since  the 
product  of  its  combustion  is  a  gas.  Were  it  a  solid, 
our  fires  would  be  choked,  and  before  each  supply 
of  fresh  fuel  we  should  be  compelled  to  remove  the 
ashes,  which  would  be  more  bulky  than  the  original 
fuel.  In  the  case  of  a  candle  or  lamp  it  Avould  be 
still  more  annoying,  as  the  solid  product  would  fall 
around  our  rooms.  Still  another  useful  property  is 
the  infusibility  of  C.  Did  C  melt  like  Zn  or  Pb  on  the 
application  of  heat,  how  quickly  in  a  hot  fire  would 


COMBUSTION, 


77 


Fig  32. 


Form  of 
flame. 


the  coal  and  wood  run  down  through  the  grate  and 
out  upon  the  floor  in  a  hquid  mass  ! 

Chemistry  of  a  Candle. — Flame  is  burn- 
ing gas.  A  candle  is  a  small  ''gas-work," 
and  its  flame  is  the  same  as  that  of  a  "gas- 
burner."  First,  we  have  a  little  cupful  of 
tallow  melted  by  the  heat  of  the  fire  above. 
The  ascending  currents  of  cool  air  which 
supply  the  light  with  0  also  keep  the  sides 
of  the  cup  hard,  unless  the  wind  blows 
the  flame  downward,  when  the  banks  break, 
there  is  a  crevasse,  and  our  "candle  runs 
down."  Next,  the  melted  tallow  is  carried 
by  capillary  attraction   up   the  small  tubes 

of  the  wick  into  the  flame.  There  it 
is  turned  into  gas  by  the  heat.  Flame 
is  always  hollow,  and  at  the  center, 
near  the  wick,  is  the  gas  just  formed. 
If  a  match  be  placed  across  a  light,  it 
will  burn  off  at  each  side,  in  the  ring 
of  the  flame,  while  the  center  will  be 
unblackened.*  The  gas  may  be  con- 
ducted out  of  the  flame  by  a  small 
pipe,  and  burned  at  a  little  distance 
from  the  candle.  Flame  is  hollow  be- 
cause there  is  no  0  at  the  center.  As 
the  gases  pass  upward  and  outward 
from   the  wick,  they   come   in   contact 


Fig.   33. 


Match  in  flame  ;  the 
S  and  P  being  vn- 
conmimed. 


*  Take  a  sheet  of  white  paper  and  thrust  it  quickly  down  upon  the 
flame  of  a  candle  or  lamp.  It  will  burn  in  a  ring,  and  when  the  paper  is 
removed  the  cent«r  will  be  found  unblackened. 


78  INORGANIC     CHEMISTRY. 

with  the  0  of  the  air,  and  the  H,  requiring  least  heat 
to  unite,  burns  first,  forming  H2O.  The  carbon  which 
was  united  with  the  H  is  now  set  free  in  tiny  par- 
ticles, Av^hich  floating  around  in  the  flame  of  the 
burning  H  become  white-hot.*  They  each  send  out 
a  delicate  wave  of  light,  and  passing  on  to  the  outer 
part    where    there    is    more    0,    burn,    forming    CO2. 

Fig.  34. 


Totting  the  CU.j  of  a  flmne  by  dratving  the  gas  through  /h/ir-irater. 

The  flame  is  l)lue  at  the  bottom,  l)ecause  thore  is  so 
much  0  at  that  point  that  the  H  and  0  burn  to- 
gether, and  so  give  little  hght. 

The  HgO  may  be  condensed  on  any  cold  surface. 
The  CO  2  may  be  tested  by  passing  the  invisible 
vapor  of  a  candle  through  lime-water. f    The  wick  of 


*  Frankland  has  shown  that  the  intensity  of  a  flame,  in  general,  is 
determined  by  the  density  of  the  gas :  thus,  a  jet  of  H  burning  under  a 
pressure  of  ten  atmospheres  will  furnish  sufficient  light  to  read  a  news- 
paper at  a  distance  of  two  feet. 

t  See  also  pages  63  and  64. 


COMBUSTION, 


79 


Fig.    35 


a  candle  does  not  burn,  because  of  the  lack  of  0  at 
the  center.  It,  however,  is  charred,  as  all  the  vola- 
tile gas  is  driven  off  by  the  heat.  If  a  portion  falls 
over  to  the  outer  part  where  there  is  0,  it  burns  as 
a  coal.  If  we  bloAV  out  a  candle  quickly,  the  gas 
still  passes  off  and  we  can  relight  it  with  an  ignited 
match  held  at  some  distance  from  the  wick.  The 
tapering  form  of  the  flame  is  due  to  the  currents  of 
air  that  sweep  up  from  all  sides  toward  it.  The 
candle  must  be  snuffed,  because  the  long  wick  would 
cool  the  blaze  below  the  igniting  point  of  C  and  0, 
and  the  C  would  pass  off  unconsumed  as  smoke.  A 
draught  of  air,  or  any  cold  substance  thrust  into 
the  flame,  produces  the  same  result  and  deposits  the 
C  as  soot.  Plaited  wicks  are 
sometimes  used,  which,  being 
thin,  fall  over  to  the  outside 
and  burn,  requiring  no  snuffing. 
V  Chemistry  of  a  Lamp.  —  A 
chimney  confines  the  hot  air, 
and  makes  a  draught  of  air  to 
feed  the  flame.  A  flat  wick  is 
used,  as  it  presents  more  sur- 
face to  the  action  of  the  0. 
Argand  lamps  have  a  hollow  wick  which  admits  air 
into  the  center  of  the  blaze,  and  thus  gives  a  larger 
luminous  surface.  The  film  which  gathers  on  a  chim- 
ney when  we  first  light  a  lamp,  is  the  HgO  produced 
in  the  flame  condensed  on  the  cold  glass.  Spirits 
of  turpentine,  tar,  pine-wood,  etc.,  contain  an  excess 
of  C,  and   not  enough  H  to   heat  it  to  the   igniting 


H.jO  condensed  from  a  flame. 


80 


INORGANIC     CHEMISTRY, 


Tig.  36. 


point.  These,  therefore,  produce  clouds  of  soot.  Alco- 
hol contains  an  excess  of  H  and  less  C,  hence  it 
gives  off  great  heat  and  little  light. 
Davy's  Safety  Lamp,  used  by 
miners,  consists  of  an  ordinary  oil- 
lamp  surrounded  by  a  cylinder  of 
fine  wire  gauze.  When  it  is  carried 
into  an  atmosphere  containing  the 
dreaded  fire-damp,  the  flame  en- 
larges and  becomes  pale,  and  when 
the  quantity  increases,  the  gas  will 
quietly  burn  on  the  inside  of  the 
cylinder.*  There  is  no  danger  of  an 
explosion  so  long  as  the  gauze  re- 
mains perfect  and  draughts  are 
avoided,  t  Through 
carelessness,  how- 
ever, fearful  acci- 
dents have  oc- 
curred. Miners  be- 
come extremely  negligent,  and  an 
account  is  given  of  an  explosion,  in 
which  about  a  hundred  persons  were 
killed,  caused  by  a  lamp  being  hung 
on  a  nail  by  a  hole  broken  through  the  wire  gauze. 

*  The  principle  of  the  lamp  can  be  illustrated  by  holding  a  ."ine  wire 
gauze  over  the  flame  of  a  candle  or  gas-burner  (Fig.  37).  The  flame  will  not 
pass  through,  since  the  wire  will  conduct  away  the  heat  and  so  reduce  the 
temperature  below  the  igniting  point.  A  jet  of  gas,  issuing  at  a  low  tem- 
perature, may  be  lighted  on  either  side  of  the  gauze  at  pleasure. 

+  At  such  a  time,  however,  the  wise  miner  will  leave  the  place  of 
danger,  lest  the  metal  should  melt  and  the  fire  escape  to  the  gas,  when  an 
explosion  would  ensue. 


Davy's  Safety  Lu)iip. 


Flame  UghUd  over 
wire  gauze. 


COMBUSTION. 


81 


The   Bunsen   Burner,  which   is  used  in  the  labo- 
ratory, consists  of  a  gas-jet,  a,  surrounded  by  a  metal 
tube,  c,  at  the  bottom  of  which  are  openings,  &,  for 
the  admission  of  air. 
The  gas  passes  up  the  ^lo-  ss. 

tube,  mingles  with 
the  air  which  it  draws 
in  through  the  open- 
ings, and  burns  at  the 
top  without  smoke. 
The  0  is  supplied  in 
sufficient  quantity  to 
burn  the  H  and  C  si- 
multaneously ;  hence 
there  is  great  heat 
with  little  light,  and 
no  soot  is  deposited 
on  the  bottom  of 
dishes  heated  by  this 
burner. 

The  Oxy-hydrogen  Blow-pipe  is  so  constructed 
that  a  jet  of  0  is  introduced  into  the  center  of  one 
of  burning  H,  thus  producing  a  solid  flame.  A  watch- 
spring  will  burn  in  it  with  a  shower  of  sparks.  Pt, 
the  most  infusible  of  metals,  will  readily  melt.  In  the 
common  flame,  as  we  have  seen,  the  little  particles 
of  solid  C,  heated  by  the  burning  H.  produce  the 
light.  As  there  is  no  solid  body  in  the  blow-pipe 
flame,  it  is  scarcely  luminous.  If,  however,  we  insert 
in  it  a  bit  of  CaO,  or  MgO,  a  dazzling  light  is  pro- 
duced.   This  is  called  the  "Drummond,"  "Lime,"  or 


The  Bunsen  Burner. 


82 


INORGANIC     CHEMISTRY. 
Pig.  39. 


The  Oxy-hyiiroijen  Blotv-pipe. 

"Calcium"  Light,  and  with  a  properly  arranged  re- 
flector has  been  seen  at  a  distance  of  one  hundred 
and  eight  miles. 


COMBUSTION. 


83 


Fig.  40. 


7 


Mouth  Blow-pipe. — In  the  common  blow-pipe,  used 

by  jewelers  and  mineralogists,  a  current  of  air  from 

the    mouth*   is    thrown    across    the 

light  just  above  the  wick.    The  fianie 

loses  its  brilliancy  and  is  driven  one 

side  in  the  form  of  a  cone  (Fig.  41). 

Its  size,  also,  is  less,  and  since  the 

combustion    is    concentrated   into    a 

smaller    space,    its    temperature    is 

higher    than    that    of    an    ordinary 

flame.    The  hottest  point  is  at  5,  a 

little   beyond   the   tip   of   the   inner 

blue  cone,  because  at  this  place  the 

combustion  is  most  complete.    The 

inner   cone   contains   CO    in    excess, 

hot  and  ready  to  combine   with   0 

from   any   substance   exposed  to   it, 

and  is  therefore  called  the  reducing 

flame.    The  outer  envelope  contains 

the  0  in  excess,  borne 
forward  by  the  jet  of 
flame,  highly  heated 
by  it,  and  ready  to 
unite  with  a  metallic 
body.  It  is  therefore 
called  the  oxidizing 
flame. — Example:  Hold 
a    copper    cent   in   the 

"  reducing    flame " ;    its    rust,    copper    oxide,   will   be 


Common  Blow-pipes. 


Fig.  41. 


*  The  air  must  come  from  the  mouth  by  the  action  of  the   muscles  of 
the  cheeks,  not  from  the  lungs. 


84  INORGANIC     CHEMISTRY. 

cleaned  off,  and  the  metal  will  shine  as  brightly  as 
if  just  from  the  mint.  In  the  "  oxidizing  flame "  a 
film  of  copper  oxide  will  be  formed  over  the  sur- 
face, and  as  we  move  the  cent  the  most  beautiful 
play  of  colors  will  flash  from  side  to  side.* 


PRACTICAL    QUESTIONS. 

1.  Why  will  pine-wood  ignite  more  easily  than  maple? 

2.  Why  is  fire-damp  more  dangerous  than  choke-damp? 

3.  Represent  the  I'eaction  in  making  COg,  showing  the  atomic  weights, 
as  in  the  preparation  of  O  on  page  12. 

4.  Should  one  take  a  light  into  a  room  where  the  gas  is  escaping? 

5.  Why  does  it  dull  a  knife  to  sharpen  a  pencil? 

6.  "V\Tiere  was  the  C,  now  contained  in  the  coal,  before  the  Carbon- 
iferous age? 

7.  Must  the  air  have  then  contained  more  plant  food  ?    (p.  58.) 

8.  What  is  the  principle  of  the  aquarium? 

9.  What  test  should  be  employed  before  going  down  into  an  old  well 
or  cellar? 

10.  What  causes  the  sparkle  of  wine,  and  the  foam  of  beer? 

11.  What  causes  the  cork  to  fly  out  of  a  catsup  bottle  ? 

12.  What  physical  principle  does  the  solidification  of  COj  illustrate? 

13.  Why  does  the  division  in  the  chimney  shown  in  Fig.  29  produce 
opposite  currents? 

14.  What  causes  the  unpleasant  odor  of  coal-gas?    Is  it  useful? 

15.  What  causes  the  sparkling  often  seen  in  a  gas-light? 

16.  Why  does  H  in  burning  give  out  more  heat  than  C? 

17.  Why  do  not  stones  burn  as  well  as  wood? 

18.  Why  does  not  hemlock  make  "  a  good  bed  of  coals "  ? 

19.  What  adaptation  of  chemical  affinities  is  shown  in  a  light? 

20.  Wliy  does  snuffing  a  candle  brighten  the  flame? 

21.  Why  is  the  flame  of  a  candle  red  or  yeUow,  and  that  of  a  kerosene 
oil  lamp  white? 

*  Introduce  a  small  piece  of  common  flint-glass  tube  into  the  redvcing 
flame.  The  glass  will  become  opaque  and  black,  because  the  Pb  will  be 
reduced  from  the  transparent  form  of  silicate  to  the  opaque  condition  of 
metal.  AVhen  this  has  happened,  place  the  black  portion  just  in  front  of 
the  oxidizing  flame.  The  discoloration  wiU  slowly  disappear,  and  the  Pb 
will  recombine  with  O  from  the  air  and  the  glass  again  become  transparent. 


THE     ATMOSPHERE.  85 

28.  Why  does  a  street  gas-light  burn  blue  on  a  windy  night?  Is  the 
light  then  as  intense?    The  heat? 

23.  Why  does  not  the  lime  burn  in  a  calcium-light? 

24.  Why  is  a  candle-flame  tapering? 

25.  Why  does  a  draught  of  air  cause  a  light  to  smoke? 

26.  What  makes  the  coal  at  the  end  of  a  candle-wick? 

27.  Which  is  the  hottest  part  of  a  flame? 

28.  Why  does  not  a  candle-wick  burn? 

29.  How  does  a  chimney  enable  us  to  bum  without  smoke  highly  car- 
boniferous substances  like  oil? 

30.  How  much  CO,  in  200  lbs.  of  chalk? 

31.  What  weight  of  CO,  in  a  ton  of  marble? 

32.  Why  does  not  a  cold  saucer  held  over  an  alcohol  flame  blacken,  as 
it  does  over  a  candle  or  gas-light? 

33.  How  much  CO,  is  formed  in  the  combustion  of  one  ton  of  C  ? 

34.  What  weight  of  C  is  there  in  a  ton  of  CO,  ? 

35.  How  miich  O  is  consumed  in  burning  a  ton  of  C  ? 

36.  ^Vhat  weight  of  sodium  carbonate  (Na^COj,  "carbonate  of  soda") 
would  be  required  to  evolve  12  grams  of  CO^? 

37.  How  much  CO,  will  be  formed  in  the  combustion  of  30  grams 
of  CO? 

38.  What  weight  of  CaCOa  would  be  required  to  evolve  12  grams  of  CO,  ? 

39.  What  would  be  the  volume  of  these  12  grams  of  CO,,  at  12°  C.  and 
744  mm.  ? 

40.  How  much  C  would  be  necessary  to  furnish  CO^  enough  to  fill  a 
gas-holder  10  meters  high  and  4  meters  in  diameter  when  the  temperature 
is  25°  C.  and  the  barometer  stands  at  754  mm.  ? 

41.  Write  in  double  columns  the  different  properties  of  carbon  dioxide 
and  carbon  monoxide ;  thus, 

CO,    is  I  CO   is 

1,  non-inflammable.  I  1,  inflammable. 


THE     ATMOSPHERE. 

The  "air  we  breathe"  consists  chiefly  of  N  and 
0,  mixed  in  the  proportion  of  79  parts  of  N  to  21 
of  0  by  volume,  or  77  of  N  to  23  of  0  by  weight. 
Besides  the  N  and  0,  air  always  contains  CO  2  and 
watery  vapor,  the  former  amounting  in  volume  to  4 
parts  in  10,000,  and  the  latter  varying  in  amount. 
Another  gas,  argon,  occurs  in  small  quantities. 


86  INORGANIC     CHEMISTRY. 

A  very  clear  idea  of  the  proportion  of  these  several 
constituents  may  be  formed  by  conceiving  the  air, 
not  as  now  dense  near  the  surface  of  the  earth,  and 
gradually  becoming  rarefied  as  we  ascend,*  but  of  a 
density  throughout  equal  to  that  which  it  now  pos- 
sesses near  the  earth.  The  atmosphere  would  then 
be  about  five  miles  high.  The  vapor  would  form 
upon  the  ground  a  sheet  of  HgO  five  inches  deep, 
next  to  this  the  CO2  a  layer  of  18  feet,  then  the  0 
a  layer  of  one  mile,  and  last  of  all  the  N  one  of  four 
miles. t — Graham.  In  this  arrangement  we  have  sup- 
posed the  gases  to  be  placed  in  the  order  of  their 
specific  gravity.  The  atmosphere  is  not  thus  com- 
posed in  fact,  the  various  gases  being  equally  min- 
gled throughout,  in  accordance  with  a  principle  called 
the  '^Laiv  of  the  diffusion  of  Gases.''  If  we  throw  a 
piece  of  lead  into  a  brook,  it  will  settle  instantly  to 
the  bottom  by  the  law  of  gravitation  and  will  remain 
there  by  the  law  of  inertia.  But  if  we  throw  into 
the  atmosphere  a  quantity  of  CO2,  it  will  sink  for 
an  instant,  then  immediately  begin  to  mingle  with 
the  surrounding  air  and  soon  become  dissipated. — 
Example :  If  we  invert  an  open-mouthed  bottle  full 
of  H  over  another  full  of  CO2,  the  H,  light  as  it  is, 
will  sink  down  into  the  lower  jar ;  and  the  COo, 
heavy  as  it  is,  will  rise  into  the  upper  jar ;  and  in  a 
few  hours   the   gases  will   be   found   equally   mixed. 

*  At  a  height  of  about  38  miles  the  air  is  only  yio  as  dense  as  at  the 
surface  of  the  earth.  At  a  height  of  50  miles  it  is  so  extremely  rare  that 
this  is  usually  given  as  the  height  of  the  atmosphere. 

t  The  N  and  O  form  so  large  a  part,  that  they  are  considered  in  ordi- 
dinary  calculation  to  compose  the  whole  atmosphere. 


THE     ATMOSPHERE. 


87 


Fig.  42. 


r 


By  this  law  the  proportion  of  the  elements  of  the 
atmosphere  is  the  same  every-where,  and  has  not 
varied  within  historic  times.  Samples  have  been 
analyzed  from  every  conceivable  place,  from 
polar  and  torrid  regions,  from  prairies  and 
mountain -tops,  from  balloons  and  mines, 
from  crowded  capitals  and  lonesome  forests, 
and  even  from  bottles  found  sealed  up  in 
the  ruins  of  Herculaneum,  and  the  result  is 
almost  exactly  the  same.  These  gases  do 
not  form  a  chemical  compound,  but  a  mere 
mechanical  mixture,*  and  they  are  as  dis- 
tinct in  the  air  as  so  man}^  grains  of  wheat 
and  corn  mingled  in  a  measure. 

Each  of  the  constituents  of  the  air  has 
its  separate  use  and  mission.  The  action  of 
0  and  N  we  have  already  seen. 

Uses  of  COg.    Carbonic  acid,  so  deadly  to 
animal  life,  is  necessary  to  the  maintenance  of  the 
vegetable  kingdom-.    The  leaf  through  its  million  of 
little  stomata,  or  mouths,  drinks  in  the  CO 2-    In  that 
minute  leaf-laboratory,  by  the  action  of  the  sunbeam, 

*  "To  illustrate  the  difference  between  a  mechanical  mixture  and  a 
chemical  compound,  mix  powdered  S  and  filings  of  Cu.  The  color  of  the  S 
as  well  as  that  of  the  Cu  \n.\\  disappear,  and  to  the  unaided  eye  will  pre- 
sent a  uniform  greenish  tint;  with  the  microscope,  however,  the  particles 
of  Cu  may  be  seen  lying  by  the  side  of  those  of  S ;  and  we  can  wash  away 
the  lighter  S  with  H^O,  leaving  the  heavier  Cu  behind.  Here  no  chemical 
action  has  occurred ;  the  S  and  Cu  were  only  mechanically  mixed.  If  we  next 
gently  heat  some  of  the  mixture  it  soon  begins  to  glow,  and  on  examining 
the  mass  we  find  that  both  the  Cu  and  the  S  have  disappeared  as  such, 
that  they  can  not  be  distinguished  even  with  the  most  powerfxil  micro- 
scope, and  that  in  their  place  we  have  formed  a  black  substance  possessing 
properties  entirely  different  from  those  possessed  either  by  the  Cu  or 
the  S."— RoscoE. 


Diffu- 
sion of 


88  INORGANIC     CHEMISTRY. 

the  CO2  is  decomposed,*  the  C  being  applied  to  build 
up  the  plant,  and  the  0  returned  to  the  air  for  our  use. 
Plants  give  out  0  as  we  breathe  out  CO2.  We 
furnish  vegetables  with  air  for  their  use,  and  they  in 
turn  supply  us.  There  is  thus  a  mutual  dependence 
between  the  animal  and  the  vegetable  world.  Each 
relies  upon  the  other.  Deprived  of  plants,  we  should 
soon  exhaust  the  0  from  the  air,  supply  its  place  with 
CO  2,  and  die ;  while  they,  removed  from  us,  would 
soon  exhaust  the  CO2,  and  die  as  certainly.  We  pol- 
lute the  air  while  they  purify  it.  Each  tiny  leaf 
and  spire  of  grass  is  thus  imbibing  our  foul  breath, 
and  returning  it  to   us  pure  and   fresh. f     This  inter- 

*  "  In  order  to  decompose  carbonic  acid  in  our  laboratories,  we  are 
obliged  to  resort  to  powerful  chemical  agents,  and  to  conduct  the  process 
in  vessels  composed  of  resisting  materials,  under  all  the  violent  manifesta- 
tions of  light  and  heat,  and  we  then  succeed  in  liberating  the  carbon  only 
by  shutting  up  the  oxygen  in  a  still  stronger  prison  ;  but  under  the  quiet 
influences  of  the  sunbeam,  and  in  that  most  delicate  of  all  structures,  a 
vegetable  cell,  the  chains  which  unite  together  the  two  elements  fall  off, 
and,  while  the  solid  carbon  is  retained  to  build  up  the  organic  structure, 
the  oxygen  is  allowed  to  return  to  its  home  in  the  atmosphere.  There  is 
not  in  the  whole  range  of  chemistry  a  process  more  wonderful  than  this. 
We  return  to  it  again  and  again,  with  ever  increasing  wonder  and  admira- 
tion, amazed  at  the  apparent  inefficiency  of  the  means,  and  the  stupendous 
magnitude  of  the  result.  When  standing  before  a  grand  conflagration,  wit- 
nessing the  display  of  mighty  energies  there  in  action,  and  seeing  the 
elements  nishing  into  combination  with  a  force  which  no  human  agency 
can  withstand,  does  it  seem  as  if  any  power  could  undo  that  work  of 
destruction,  and  rebuild  those  beams  and  rafters  which  are  disappearing 
in  the  flames?  Yet  in  a  few  years  they  will  be  rebuilt.  This  mighty  force 
will  be  overcome ;  not,  however,  as  we  might  expect,  amidst  the  convul- 
sion of  nature,  or  the  clashing  of  the  elements,  but  silently,  in  a  delicate 
leaf  waving  in  the  sunshine."— Cooke. 

+  From  this  statement  it  is  evident  that  the  foliage  of  house-plants 
must  be  healthful.  Moreover,  there  is  some  reason  to  believe  that  the  O 
which  they  exhale  is  highly  ozonized,  and  therefore  of  great  value  in 
destroying  miasmic  germs.  We  should  remember,  however,  that  flowers 
exhale  COa ,  and  the  odor  of  certain  plants,  and  the  pollen  of  others,  are 


THE     ATMOSPHERE, 
Fig.  43. 


89 


Wi^^^^iiiU 


Apparatus  arranged  to  caich  the  O  ewlved  from  a  spng  oj  leaves. 

change  of  office  is  so  exactly  balanced,  that,  as  we 
have  seen,  the  variation  in  the  proportion  of  COg  and 
of  0,  in  the  open  air,  is  almost  imperceptible.* 

very  injurious.  Plants  and  flowers,  which  to  one  person  are  inocuous,  are 
to  another  detrimental.  Thus  the  fragrance  of  new-mown  grass,  which  is 
so  agreeable  to  some,  produces  in  others  what  is  termed  the  hay-fever ;  due, 
it  is  said,  to  the  pollen  of  the  grass.  Each  family,  therefore,  must  deter- 
mine for  itself  what  should  be  excluded  from  its  collection.  It  is  e\adent 
that  flowerless  plants,  like  the  ivy,  etc.,  are  harmless,  while  the  cheerful- 
ness given  to  an  apartment  by  even  a  few  pots  of  flowers  on  a  window- 
bench,  should  induce  one  to  take  some  trouble  in  order  to  make  a  selection 
which  will  not  only  beautify  but  purify  the  room. 

*  "Two  hundred  million  tons  of  coal  are  now  annually  burned,  pro- 
ducing six  hundred  million  tons  of  CO„.  A  century  ago,  hardly  a  fraction 
of  that  amount  was  burned,  yet  this  enormous  aggregate  has  not  changed 
the  proportion  in  the  least."— Youmans. 


90  INORGANIC     CHEMISTRY. 

1/ Plants  Store  up  Solar  Energy.  —  The  sunbeam, 
which  is  thus  strong  enough  to  wrench  apart  the  C 
and  0,  sends  out  the  0  full  of  potential  energy  and 
builds  up  the  plant.  The  energy  of  the  sunbeam  is 
transformed  into  the  potential  energy  of  0  and  of  the 
vegetable  structure.  The  sun  shining  on  a  meadow 
causes  the  grass  to  grow.  In  this  process  energy  of 
the  sun  is  absorbed,  which  is  again  rendered  available 
as  active  energy  by  the  animal  which  feeds  upon  the 
grass.  A  tree  towers  upward  through  a  century  of  sun- 
shine. When  burned,  it  sets  free  as  much  energy  as 
was  needed  to  perfect  its  growth.  A  bushel  of  corn, 
then,  represents  not  alone  so  much  C,  H,  and  0,  but  also 
an  amount  of  sun-energy  which  is  available  for  any 
purpose  to  which  we  wish  to  apply  it.  (See  Con- 
clusion.) 

Animals  Spend  Solar  Energy. — In  the  process  of 
digestion  the  energy  stored  in  the  plant  is  trans- 
ferred to  the  animal,  is  given  out  by  its  muscles  on 
their  oxidation  and  produces  motion,  heat,  etc.  NH3, 
CO2,  and  H2O  are  decomposed  by  the  plant  and 
organized  into  complex  molecules  (see  p.  185),  full 
of  potential  energy.  The  animal  oxidizes  the  organic 
molecules,  and  breaks  them  up  into  NH3,  CO2,  and 
H2O  again — simple  molecules  robbed  of  energy  which 
the  animal  has  used.  Thus  the  plant  builds  up  and 
the  animal  tears  down.  The  plant  garners  in  the 
sunbeam  and  the  animal  scatters  it  again.  The 
plant  reduces  and  the  animal  oxidizes. 

Uses  of  Watery  Vapor. — We  have  already  seen 
the  uses  of  H2O.     As  vapor,  it  is  every-where  present 


THE     ATMOSPHERE,  91 

and  ready  to  supply  the  wants  of  animals  and  plants. 
Were  the  air  perfectly  dry,  our  flesh  would  become 
shriveled  like  a  mummy's,  and  leaves  would  wither 
as  in  an  African  simoom.  Rivers  and  streams  flow 
to  the  ocean  ;  yet  all  their  fountains  are  fed  by  the 
currents  that  move  in  the  air  above  us.  H2O  rises 
as  vapor,  flows  on  to  colder  regions,  falls  as  rain, 
sleet,  snow,  or  hail,  and  then  wends  its  Avay  back  to 
the  ocean,  turning  many  a  water-wheel  on  its  way 
as  it  parts  with  its  potential  energy. 

Permanence  of  the  Atmosphere.  —  The  elements 
of  the  air  unite  to  form  HNO3  only  by  the  passage 
of  electricity,  and  then  in  minute  quantities.  If  they 
combined  more  readily  we  should  be  constantly  ex- 
posed to  a  shower  of  this  corrosive  acid  that  would 
be  destructive  to  all  vegetation,  clothing,  and  even 
our  bodies  themselves. — 0,  N,  and  CO 2  are  converted 
into  liquids  only  by  an  apparatus  specially  made 
for  the  purpose,  and  under  circumstances  which 
could  rarely,  if  ever,  occur  in  Nature.*  These  sub- 
stances are  therefore  constantly  in  the  condition 
promptly  to  supply  the  demands  of  animals  and 
plants. — Watery  vapor,  on.  the  contrary,  is  deposited 
as  dew  or  rain  by  even  slight  changes  of  tem- 
perature ;  this  readiness  of  condensation  is  equally 
necessary  to  meet  the  wants  of  animal  and  vege- 
table life. 


*  The  liquefaction  of  the  so-called  "permanent  gases."  N,  O,  H,  etc.,, 
was  first  accomplished  in  1877  by  Oailletet  of  Paris  and  Pictet  of  Oeneva, 
almost  simultaneously. 


92  INORGANIC     CHEMISTRY. 

THE     HA  LOG  ENS. 

Chlorine. .  Symbol,  CI;  fi^iomk  Weight,  35.5;  Specific  Gravity,  2.45, 

Iodine....       "         1;  "          "  127.;  "                    4,95. 

Bromine..       "       Br;  "           "  80.;  "                     3.19. 

Fluorine..       "         F;  "           "  19. 

These  four  elements  are  closely  allied,  and  are 
known  as  the  halogens,  from  hals,  salt,  because  they 
form  a  class  of  compounds  (Haloids)  which  resemble 
common  salt  (NaCl).* 

Chlorine  is  named  from  its  green  color.  It  is 
chiefly  found  in  salt,  of  which  it  forms  60  per  cent. 
It  iTiay  be  prepared  by  gently  heating  a  mixture 
Mn02  ^'i^tl  hydrochloric  acid: 

MnOa  +  -IHCl  =  MnCl2  +  ^HjO  +  2C1  ; 

or  still  more  conveniently  from  NaCI,  MnOs,  and  H2SO4. 
On  slightly  warming  this  mixture  a  regular  and 
copious  evolution  of  CI  takes  place.  CI  is  heavier 
than  common  air,  and  hence  may  be  collected  by 
displacement,  as  in  the  preparation  of  COg. 
y  Properties. — CI  has  a  greenish-yellow  color,  and  a 
peculiarly    disagreeable    odT)r.      Tt    produces    a    sufTo- 

*  In  comparing  the  lialogcns  with  one  another,  the  chemical  activity  of 
P,  which  has  the  smallest  atomic  weight,  is  the  most  powerful ;  next  in 
the  order  of  activity  is  CI,  then  Br,  and,  lastly,  I,  the  atomic  weight 
increasing  as  the  chemical  energy  declines.  CI  is  gaseous,  Br,  liquid,  and 
I  solid.  The  specific  gravity,  the  fusing  point,  and  the  boiling  point, 
rise  as  the  atomic  weight  increases.  The  halogens  combine  energetically 
with  the  metals,  and,  when  united  with  the  same  metal,  furnish  com- 
pounds which  are  inomnrphmiK ;  that  is  to  say.  thoy  all  ci-ystalliKe  in  the 
same  form— potassium  fluoride,  chloride,  bromide,  and  iodide,  for  example, 
all  crystallize  in  cubes.  Each,  also,  forms  with  H  a  soluble,  powerful  acid 
-HCl,  HI,  HBr,  HP. 


THE     HALOGENS. 
Fig.   44. 


93 


Preparing  CI. 


eating  cough,  which  can  be  reUeved  by  breathing 
ammonia  or  ether.  It  is  incombustible.  If  a  Hghted 
candle  is  lowered  into  a  jar  of  CI,  it  burns  Avith  a 
red  smoky  flame  for  a  short  time,  and  then  goes 
out.  Arsenic,  Dutch  gold-leaf,  phosphorus,  etc.,  com- 
bine with  it  so  rapidly  as  to  inflame.  Powdered 
antimony  slowly  dropped  into  it  produces  a  shower 
of  brilliant  sparks.  Cold  water  absorbs  about  twice 
its  volume  of  the  gas. 

CI  has  a  very  strong  affinity  for  H.  When  H  and 
CI  are  mixed  in  the  dark  and  exposed  to  direct  sun- 
light, they  unite  with  an  explosion  ;  and  CI  is  able 
to  take  H  away  from  its  combination  with  other 
substances.  Thus  it  acts  energetically  on  turpen- 
tine  (CioHig),   uniting   with   its    H    and   setting  its   C 


94 


INORGANIC     CHEMISTRY. 


free   in   a  great  cloud   of  soot.    Another  example  is 

seen  in  the  way  in  which 


Frr,.  45. 


Fig.  4C. 


Caudle  ill  CI. 


Turpentbu.  in  CI. 


a  candle  burns  in  the 
gas.  It  will  even  decom- 
pose water  to  get  H,  set- 
ting 0  free  in  the  process. 
This  action,  like  the  di- 
rect union  of  H  and  CI, 
does  not  take  place  in 
the  dark ;  but  if  chlorine 
water  is  exposed  to  direct 
sunlight,  it  goes  on  slowly 
and  the  0  can  be  col- 
lected and  tested.     The  reaction  is  represented  l)y  the 

equation : 

HgO  +  2C1  =  2HC1  +  0. 

This  same  reaction  also  takes  place  without  the 
aid  of  sunlight  when  there  is  some  substance  present 
on  which  the  0  can  readily  act.  Such  substances 
are  organic  coloring  matters,  and  hence  CI  can  de- 
stroy many  dye-stuffs  and  thus  bleach  cloth,  etc.,  in 
the  presence  of  moisture.  Upon  some  dyes  it  probabl}^ 
acts  directly,  converting  them  into  colorless  sub- 
stances, but  in  many  cases  the  color  is  discharged 
only  when  moisture  is  present.  In  such  cases  the 
bleaching  is  a  burning  or  oxidation,  and  hence  CI  is 
called  an  "indirect  oxidizing  agent."  The  necessity 
for  the  presence  of  moisture  is  shown  by  placing  two 
strips  of  colored  calico  or  of  litmus  paper,  one  dry 
the  other  moistened,  in  different  jars  of  dry  CI.  The 
0    is   set   free   by   the   CI   in   the   nascent  state,   and 


THE     HALOGENS.  95 

hence  produces  an  effect  of  which  the  atmospheric 
0  is  incapable.  CI  discharges  the  color  of  indigo, 
"writing-ink,  wine,  etc.,  almost  instantaneously,  but 
has  no  effect  on  printer's  ink,  the  basis  of  which  is 
C,  nor  on  mineral  colors  in  general. 

Uses.  —  Bleaching.  —  In  domestic  bleaching  the 
cloth  is  first  boiled  with  strong  soap,  to  dissolve  the 
grease  and  wax,  and  then  laid  upon  the  grass,  being 
frequently  wet  to  hasten  the  action  of  the  air  and 
sun.'''  It  seems  likely  that  ozone  is  formed  by  the 
evaporation  of  the  moisture,  and  that  the  bleach- 
ing is  really  an  oxidation  by  its  means.  CI  is  now 
extensively  used  for  bleaching  cloth,  paper-pulp, 
etc.f  It  is  usually  employed  in  the  form  of  so-called 
"  chloride  of  lime  "  or  l)leaching  powder. 

Disinfectant.  —  CI  is  a  powerful  disinfectant.  It 
breaks  up  the  offensive  substance  by  uniting  with 
its  H  as  in  bleaching.  Other  disinfectants,  as  burnt 
paper,  sugar,  etc.,  only  disguise  the  ill  odor  by  sub- 
stituting a  stronger  one.     In   the   sick-room  CI  is  set 

*  This  was  essentially  the  process  long  pursued  in  Holland,  where  linens 
were  formerly  carried  for  bleaching;  hence  the  term  "Holland  linen," 
still  in  use.  The  H-^O  about  Haarlem,  was  thought  to  have  pectdiar  proper- 
ties, and  no  other  could  compete  with  it.  Cloths  sent  there  were  kept  the 
entire  summer,  and  were  returned  in  the  fall.  Later  a  similar  plan  was 
adopted  in  England.  But  the  vast  extent  of  grass-land  required,  the  time 
occupied,  and  the  temptation  to  theft,  made  the  process  extremely  tedious 
and  expensive.  The  statute  laws  of  that  time  abound  in  penalties  for 
cloth  stealing.  It  is  estimated  that  all  the  men,  women,  and  children 
in  the  world  could  not,  by  the  old  way,  bleach  all  the  cloth  that  is  now 
\ised. 

+  stains  can  be  removed  from  unwlored  doth  by  "  LabaiTaque's  Solution," 
a  compound  of  CI,  which  can  be  obtained  of  any  druggist.  Place  the  cloth 
in  this  liquid,  and  if  the  stain  is  obstinate,  pour  on  a  little  boiling  H^O, 
or  place  it  in  the  sun  for  some  hours.  Then  rinse  thoroughly  in  cold  H^O 
and  dry. 


90  INORGANIC     CHEMISTliY. 

free  from  chloride  of  lime  (bleaching  powder)  by 
exposing  it  to  the  air  in  a  saucer  with  a  little  HgO. 
The  gas  gradually  passes  off,  being  set  free  by  the 
action  of  the  COg  in  the  air,  and  the  process  may 
be  hastened  by  adding  a  few  drops  of  dilute  acid. 
Chloride  of  lime  is,  therefore,  of  great  service  for 
disinfecting  all  places  exposed  to  any  noxious  or 
unpleasant  effluvia.  Hospitals  and  rooms  in  which 
persons  have  died  of  a  contagious  disease  are  puri- 
fied by  placing  in  them  pans  full  of  a  mixture  which 
is  disengaging  CI  in  large  quantities. 

Compounds. — Hydrochloric  Acid,  Mii/riatic  Acid, 
HCl. — CI  and  H  form  only  this  one  compound,  and  it 
is  produced  whenever  CI  acts  upon  H  or  any  sub- 
stance (e.  g.,  water,  H  g  0)  which  contains  H.  If 
a  lighted  jet  of  H  be  brought  into  a  jar  of  CI,  the 
flame  becomes  whitish,  the  greenish  CI  disappears 
and  a  gas  is  formed  which  fumes  as  it  escapes  from 
the  jar. 

HCl  is  prepared  hj  treating  common  salt  (NaCl) 
with  H2SO4: 

2NaCl  +  H2SO4  =  Na2S04  +  2HCI 

Properties. — It  is  an  irrespirable,  irritating,  acid 
gas,  with  an  intense  attraction  for  HgO,  which  causes 
it  to  produce  white  fumes  in  the  air.  Water  at  60°  F. 
will  absorb  over  450  times  its  volume  of  the  gas,* 
producing   the    liquid    known    as   ^^  Hydrochloric '^   or 

♦  The  great  solubility  of  HCl  in  water  can  be  shown  by  an  experiment 
like  that  employed  to  demonstrate  the  solubility  of  NH3  (see  p.  36).  Tf 
the  water  be  colored  with  blue  litmus,  it  will  turn  red  as  it  comes  into 
the  bottle. 


THE     HALOGENS. 
Fig.  47. 


97 


Preparing  HCl. 

^^  Mv/riatic  AcidJ'  This  dissolves  many  metals  with 
evolution  of  H  and  formation  of  chlorides.  When 
pure  it  is  colorless,  but  has  ordinarily  a  yellow  tinge, 
due  to  various  impurities.  Its  tests  are  NH3,  with 
which  it  forms  a  white  cloud  of  sal-ammoniac  fumes, 
and  silver  nitrate,  from  which  it  precipitates  AgCl. 
With  HNO3  it  makes  aqua  regia,*  or  royal  tuater,  so 
called  because  it  dissolves  Au,  the  "king  of  the 
metals " ;  CI  is  set  free,  which,  in  its  nascent  .state, 
attacks  the  Au  and  combines  with  it. 
\/  Acids,  Bases,  and  Salts. — We  have  seen  that  when 
gaseous  NH3  and  HCl  come  together,  they  unite  with 
the  formation  of  a  white  cloud.  The  same  substance 
is  produced  when  a  solution  of  HCl  is  poured  into  a 
solution    of    NH3,    and    may   be    obtained    as  a   white 

*  Boil  HCl  in  a  test  tube  with  fragments  of  gold-leaf.  They  wiU  not 
dissolve.  Add  a  few  drops  of  HNO^,  and  a  yellow  solution  of  gold  chloride 
will  be  quickly  formed. 


98  INORGANIC     CHEMISTRY. 

powder  by  evaporating  off  the  water.  We  have  also 
seen  that  NH3  or  its  solution  turns  red  litmus  bhie, 
and  that  HCI  or  its  solution  turns  blue  litmus  red. 
Now,  if,  before  pouring  the  hydrochloric  acid  into 
the  NH3  solution,  a  little  litmus  be  added  to  the  lat- 
ter, it  will  be  found  that  it  remains  blue  until  a 
certain  quantity  of  the  acid  has  been  poured  in,  and 
that  then  the  color  suddenly  changes  to  red.  The 
point  at  which  this  change  takes  place  may  be  hit  so 
exactly  that  a  drop  of  acid  will  turn  the  solution  red, 
or  a  drop  of  NH3  solution  blue.  At  this  point  the  so- 
lutions are  said  to  have  neutralized  each  other,  since 
the  distinctive  character  of  each  has  disappeared. 

These  solutions  and  the  product  of  their  action 
on  each  other  may  stand  as  types  of  those  verj^  im- 
portant classes  of  chemical  compounds :  the  acids, 
the  bases,  and  the  salts. 

The  Acids  are  generally  sour*  and  turn  vegetable 
colors — such  as  the  infusion  of  blue  litmus,  or  of 
purple  cabbage  t — to  a  bright  red.  This  will  be  seen 
to  be  the  case  with  even  very  dilute  solutions  of 
the  three  acids  with  which  we  have  thus  far  become 
familiar,  HNO3,  H2SO4,  and  HCI.  They  all  have  the 
power  of  neutralizing  NH3  solution,  and  substances 
like   it,  with   the   formation  of  compoimds  in  which 

*  Certain  acids,  as  well  as  cci-tain  bases,  are  insoluble  in  water,  and 
henco  have  no  taste.  They,  however,  combine  to  form  salts,  which  is  their 
true  test. 

+  Paper  tinged  blue  with  a  solution  of  litmus  (a  eolorinti  matter  ob- 
tained from  certain  lichens)  should  be  constantly  at  hand  in  the  laboiatory, 
to  determine  the  presence  of  a  free  acid.  The  same  paper  faintly  j-eddened 
by  vinegar,  or  any  other  acid,  is  a  convenient  test  for  the  alkalies.  The 
cabbage  solution  is  made  by  steeping  red  cabbage-leaves  in  water,  and 
straining  the  purplish  liquid  thus  obtained. 


THE     HALOGENS.  99 

the  place  of  the  H  of  the  acid  has  been  taken  by 
a  metal  or  something  which  acts  like  a  metal.  All 
acids  contain  H  which  can  be  thus  replaced. 

The  Bases  are  substances  which,  like  NH3  solu- 
tion, have  the  power  of  neutralizing  acids.  They  all 
contain  a  metal  or  something  which  acts  like  a 
metal.  The  alkalies'^  are  bases  which  are  soluble  in 
water,  have  a  soapy  taste  and  feel,  turn  red  litmus 
to  blue,  and  red-cabbage  solution  to  green,  neutralize 
the  acids  and  restore  the  colors  changed  by  them. 
The  property  ivhich  the  acids  and  bases  thus  have 
of  uniting  with  each  other  and  destroying  the  chem- 
ical activity  which  either  possesses  alone  is  their  dis- 
ti  ng  liishing  tra  it.\ 

The  Salts  are  substances  formed  by  the  neutral- 
ization of  an  acid  by  a  base.  They  may  be  defined 
as  acids  in  which  the  whole  or  part  of  the  H  has 
been  replaced  by  a  metal.  Thus  we  have  as  salts 
of  HNO3:  KNO3,  Pb2N03,  etc.;  of  HCl :  NaCl,  CaClg, 
etc.;   of  H2SO4:    NaHS04,  Na2S04,  etc. 

Nomenclature  of  Acids  and  Salts. — The  termina- 
tion   ic    is    generally   used   in   naming   acids.     Thus 


*  The  alkalies  are  ooinpoiinds  of  H,  O,  and  a  metal.  They  are  hence 
called  hydroxides;  as  KOH  (potassium  hydrate,  caustic  potash),  NaOH  (so- 
dium hydrate).  Ammonia  solution  is  supposed  to  contain  the  compound 
NH,OH  (ammonium  hydroxide),  in  which  NH^  plays  the  part  of  a  metal. 

t  To  a  part  of  the  purple-cabbage  solution  add  a  few  drops  of  a  solution 
of  caustic  potash :  a  green  liquid  will  be  produced.  To  another  portion 
add  a  few  drops  of  sulphuric  acid :  the  solution  will  become  red.  Pour  the 
red  acid  liquor  into  the  green  alkaline  one,  and  stir  the  mixture  :  the  red 
color  at  first  disappears,  and  the  whole  remains  green ;  but  on  adding  it 
cautiously,  a  point  is  reached  at  which  it  assumes  a  clear  blue  color. 
There  is  then  no  excess  of  acid  or  alkali ;  and  on  evaporation,  a  neutral 
salt,  potassium  sulphate,  may  be  obtained. 


100  INORGANIC     CHEMISTRY. 

HCl,  hydrochloric  acid;  HNO3,  nitric  acid;  H2SO4, 
sulphuric  acid.  All  the  acids  except  some  of  those 
in  which  members  of  the  halogen  group  appear, 
contain  0,  and  in  some  cases  these  differ  from 
each  other  only  in  the  proportion  of  0.  Thus,  there 
are  two  acids  containing  N  :  HNO3,  and  HNO2.  To 
distinguish  these  the  latter  is  called  rdlrous  acid ; 
and  in  general,  where  there  are  two  similar  acids 
like  these,  the  termination  ous  is  employed  in 
naming  that  containing  the  less  proportion  of  0. 
The  salts  derived  from  the  acids  that  end  in  ic 
take  the  termination  ate,  and  those  from  acids 
in  ous,  the  termination  itc.  Thus  from  HNO3  we 
have  nitrates;  from  HNO2,  nitrites.  An  exception 
to  this  rule  is  made  in  naming  the  salts  of  HCl 
and  other  halogen  acids  which  contain  no  oxy- 
gen;  their  salts  are  binary'^  compounds  and  take 
the  termination  ide.  Thus  we  have  NaCl,  sodium 
chloride,  etc. 

Bromine — named  from  its  bad  odor — is  a  poison- 
ous, volatile,  deep-red  liquid,  with  the  general  proper- 
ties of  Cl.t  It  occurs  only  in  combination,  chiefly 
with  Na  in  NaBr,  which  is  principally  found  in  sea- 
water.  Br  can  be  prepared  from  NaBr  in  the  same 
way  as  CI  from  NaCl.  With  H,  Br  forms  hydrobromic 
acid,  HBr,  which  resembles  HCl.  With  metals,  bro- 
mides are  formed  {e.g.  CdBrg),  which  are  used  in 
photography  and  in  medicine. 

♦  See  Introduction,  page  6. 

t  Br  is  the  only  element,  except  Hg,  which  is  liquid  at  ordinary  tem- 
peratures. 


THE     HALOGENS.  101 

Iodine  is  named  from  its  beautiful  violet-colored 
vapor.  It  is  made  from  kelp  (the  ashes  of  sea-weed). 
Its  salts  are  found  in  sea-water  and  in  some  mineral 
springs.  It  crystallizes  in  bluish-black  scales,  emits 
a  smell  resembling  that  of  CI,  sublimes*  slowly, 
and  is  deposited  in  crystals  on  the  sides  of  the  bot- 
tle in  which  it  is  kept.  I  is  sparingly  soluble  in 
HgO,  but  readily  in  ether  or  alcohol.  It  inflames 
spontaneously  when  in  contact  with  phosphorus-f 
Its  compounds  with  the  metals,  called  the  iodides, 
are  remarkable  for  their  variety  and  brilliancy  of 
color.  (See  Appendix.)  It  stains  cloth  a  yellowish 
tint,  which  may  be  removed  by  a  solution  of  potas- 
sium iodide.  Its  test  is  starch,  forming  the  blue 
iodide  of  starch. J  I  reveals  the  presence  of  this'  sub- 
stance in  potatoes,  wheat,  etc.§  It  is  much  used  in 
medicine,  especially  in  the  treatment  of  bruises  and 
skin  diseases. 

Fluorine  is  the  only  element  that  will  not  unite 
with  0.  It  exists,  in  small  quantities,  in  the 
enamel    of    the    teeth.      It    is    found    in    fluor    spar 

*  A  body  is  said  to  si/blime  when  it  rises  as  vapor  and  condenses  in  the 
solid  form ;  when  it  condenses  as  a  liquid  it  is  said  to  distil. 

t  Place  on  a  clean,  white  dish  a  few  scales  of  iodine  and  a  bit  of  phos- 
phorus as  large  as  a  pea.  They  will  soon  combine,  igniting  the  phosphorus 
and  subliming  a  part  of  the  iodine. 

i  Mix  one  or  two  drops  of  a  solution  of  potassium  iodide  with  a  little 
dilute  starch  mucilage ;  no  change  of  color  will  occur.  Add  a  single  drop 
of  CI  water  to  the  mixture ;  an  immediate  coloration  will  occur,  owing 
to  the  combination  of  the  CI  with  the  K,  while  I  is  set  free,  which  acts 
upon  the  starch.  Add  a  little  more  chlorine  water ;  the  color  disappears, 
o'wing  to  the  formation  of  chlorine  iodide,  which  is  without  action  on 
starch. 

§  Pour  a  few  drops  of  a  solution  of  iodine  in  alcohol  on  a  freshly-cut 
potato.    Blue  specks  will  show  the  presence  of  starch. 


102  INORGANIC    CHEMISTRY. 

(CaFg),  of  which  beautiful  ornaments  are  made. 
In  the  free  state  it  is  a  colorless  gas  of  an  odor  re- 
sembling that  of  chlorine.  It  attacks  all  metals 
violently,  combining  with  them  to  form  fluorides. 
With  H,  it  forms  hydrofluoric  acid  (HF),  noted 
for  its  corrosive  action  on  glass.  This  eats  out 
the  silica  or  sand  from  the  glass,  and  is  there- 
fore used  for  etching  labels  on  glass  bottles  and 
on  shop  windows.  —  Experimen t :  Powdered  fluor 
spar  is  placed  in  a  lead  traj^,  and  covered  with 
dilute  H2SO4.  The  heat  of  a  lamp  applied  beneath, 
for  a  moment  only,  liberates  the  gas  in  white  fumes 
very  rapidly.  The  plate  of  glass  is  covered  with 
wax,  ^and  the  design  to  be  etched  is  traced  upon 
it  with  a  sharp-pointed  instrument.  This  is  then 
laid  over  the  tray,  and  the  escaping  gas  soon  etches 
the  lines  laid  bare  into  an  appearance  like  ground 
grass.  A  solution  of  HP  in  HjO  is  often  sold  for 
this  purpose.  It  is  kept  in  lead  or  gutta-percha  bot- 
tles, combines  with  HjO  with  a  hissing  sound,  like 
red-hot  iron,  and  must  be  handled  with  care,  as  even 
a  minute  drop  will  sometimes  produce  obstinate  blis- 
ters and  sores. 


SULPHUR.  103 

SULPHUR. 

Symbol,  S.  .  .Atomic  Weight,  32.  .  .Specific  Gravity,  1.96-2.05. 

Sources. — S  is  found  native  in  volcanic  regions. 
It  is  mined  near  Mount  -^tna  in  great  quantities. 
United  with  the  metals  it  forms  sulphides,  known 
as  cinnabar,  iron  pyrites,  galena,  blende,  etc.  Com- 
bined with  0  and  metals  it  exists  in  gypsum  (plas- 
ter), heavy  spar,  and  other  sulphates.  It  is  found  in 
the  hair,  and  many  dyes  contain  Pb  which  unites 
with  the  S,  and  forms  a  black  compound  that  stains 
the  hair.  It  is  contained  in  eggs,  and  so  tarnishes 
our  spoons  by  forming  a  sulphide  of  silver.  It  is 
always  present  in  the  flesh,  and  hence  manifests 
itself  in  our  perspiration.  In  commerce  it  is  sold  as 
brimstone,  formed  by  melting  S  and  running  it  into 
molds ;  also  as  flowers  of  sulphur,  obtained  by  sub- 
limation. 

Properties.  —  It  is  insoluble  in  H2O,  and  hence 
tasteless.  Its  solvents  are  carbon  disulphide  (CS2), 
oil  of  turpentine,  and  benzene.  It  is  a  non-conductor 
of  heat,  and  crackles  when  we  grasp  it  with  a  warm 
hand.  It  may  be  obtained  in  several  allotropic  forms : 
1st,  octahedral  crystals;  2d,  prismatic  crystals;  3d,  an 
amorphous  (without  form)  or  uncrystallized  state ; 
and  4th,  a  viscid  condition.  The  last  is  the  most 
interesting. — Example  :  When  S  is  melted,  and  then 
heated  more  strongly,  it  changes  to  a  thick,  viscid, 
dark-colored  liquid  resembling  molasses.  If  this  is 
poured  into  cold  water,  it  becomes  elastic  like  India 


04 


INORGANIC     CHEMISTIIY. 


rubber.  S  is  very  much  like  oxygen  in  its  power  to 
unite  readily  with  most  of  the  elements. 

Uses. — On  account  of  its  ready  inflammability,  S 
is  employed  in  the  making  of  matches  and  gun- 
powder, but  its  chief  consumption  is  in  the  produc- 
tion of  H2SO4, 

Compounds. — Sulphur  Dioxide,  SO2,  an  irrespirable, 
suffocating  gas,  is  formed  by  S  burning  in  the  air, 
as  in  the  lighting  of  a  match.  It  is  prepared  for 
experiments  by  treating  copper  with  strong  H2SO4. 
On  heating,  SO2  is  evolved  and  may  be  collected  like 
CI  by  displacement.  The  action  of  the  acid  on  the 
copper  is  represented  thus : 

Cu  +  2H2SO4  ==  CUSO4  +  2H2O  +  SO2. 

SO2  is  more  than  twice  as  heav}^  as  air.  It  is  readily 
soluble  in  water,  forming  a  solution  which  is  be- 
lieved   to    contain    H2SO3,    sulphurous   acid.     When 

this  is  neutralized  by  bases  it 
yields  salts  called  sulphites. 
SO2  will  not  support  com- 
bustion. 

Uses. — SO2  is  made  in  large 
quantities  for  the  purpose 
of  manufacturing  sulphuric 
acid.  It  is  used  for  bleach- 
ing silk,  straw,  and  woolen 
fabrics,  which  are  destroyed  by 
CI.  Its  action  is  very  different 
from  that  of  CI,  and  depends  upon  the  power  it  has 
of  withdrawing  0  from  substances  or  reducing  them, 


Tig.  48. 


Bleaching  by  SOj. 


I 


SULPHUR.  105 

as  it  is  called.  This  takes  place  in  the  presence  of 
moisture,  and.  the  result  is  that  the  SO 2  with  HgO 
and  the  0  forms  sulphuric  acid,  H2SO4.  The  reducing 
action  of  SO2  is  made  use  of  in  the  manufacture  of 
paper,  to  destroy  the  excess  of  CI  after  bleaching : 

SO2  +  CI2  +  2H2O  =  H2SO4  +  2HCI. 

SO2  is  called  on  this  account  an  "  anti-chlor." 

The  bleaching  effected  by  SO 2  is  not  permanent 
like  that  by  CI.  The  color  is  often  restored  by  ex- 
posure to  the  air  or  by  alkalies.  S  is  also  frequently 
employed  to  check  fermentation,  as  when  it  is  burned 
in  a  barrel  before  filling  with  new  cider. 

Sulphur  Trioxide,  SO3,  may  be  prepared  by  the 
oxidation  of  SO  2  in  the  presence  of  platinum  sponge. 
It  is  often  called  sulphuric  anhydride/^  If  Nord- 
hausen  acid  f  be  heated,  the  vapors  may  be  con- 
densed in  a  mass  of  silky,  crystalline  fibers  of  SO3. 
"  This  will  show  no  acid  reaction,  will  not  redden  blue 
litmus-paper,  and,  if  the  fingers  are  dry,  can  be 
molded  like  w^ax.  If  it  be  dropped  into  H2O,  it  will 
hiss  like  a  red-hot  iron,  and  forming  H2SO4,  will  ex- 
hibit all  the  properties  of  that  corrosive  substance. 

Sulphuric  Acid,  Oil  of  Vitriol,  is  the  king  of  the 
acids.  It  is  of  the  utmost  importance  to  the  manu- 
facturer and  chemist,  as  it  is  used  in  the  preparation 
of  nearly  all  other  acids,  and  many  valuable  com- 
pounds. 

*  An  anhydride  (without  water)  is  a  substance  which,  when  dissolved 
in  H2O,  will  unite  with  its  elements  and  form  an  acid. 

t  So  named  from  the  Q-erman  town  near  which  it  was  formerly  made 
by  the  distillation  of  green  vitriol  (iron  sulphate). 


106  INORGANIC     CHEMISTRY. 

Preparation. — H2SO4  is  such  a  strong  acid  that  it 
can  not  be  made  by  the  action  of  some  other  acid 
on  its  salts,  the  sulphates,  as  HNO3  is  made  from 
nitrates  and  HCl  from  chlorides.  It  is  always  made  by 
oxidizing  sulphurous  acid,  or  what  comes  to  the  same 
thing,  oxidizing  SO 2  in  the  presence  of  moist- 
ure. If  we  burn  a  little  S  in  a  bottle,  it  will 
soon  become  filled  with  SO2.  Nitric  acid,  it 
will  be  remembered,  easily  parts  with  its  0. 
So  if  we  stir  the  SO2  with  a  swab  wet  in 
aqua  fortis,  we  shall  quickly  see  the  familiar 
NO2  fumes,  indicating  that  the  acid  has 
been  decomposed  and  has  given  up  0.  Add 
a  little  water  and  shake  the  jar  thoroughly. 
On  testing  the  liquid  with  a  few  drops  of  a  solution 
of  barium  chloride,  a  beautiful  white  precipitate  will 
prove  the  presence  of  H2SO4.* 

The  Manufacture  of  Sulphuric  Acid  on  a  large 
scale  is  based  on  the  principle  of  the  preceding  illus- 
tration. The  process  is  facilitated  by  the  curious 
fact  that  nitric  oxide  (NO)  has  the  property  of  act- 
ing as  a  carrier  of  0  between  the  common  air  and 
H2SO3,  whereby  it  can  oxidize  an  almost  indefinite 
quantity,  thus  forming  H2SO4.  S  is  burned  in  a  cur- 
rent of  air  in  furnaces  A,  A.  In  the  stream  of 
heated  gas  is  suspended  an  iron  pot,  h,  charged  with 
a  mixture  of  sodium  nitrate  and  H2SO4..  Vapors  of 
HNO3  are  thus  set  free,   and   these   pass   on    niixed 

*  The  reaction  in  making  the  acid  may  be  thus  expressed : 
2HNO3  +  3SO2  +  2H2O  =  SHjSO.  +  2N0. 
The  NO  is  at  once  converted  into  NOj  by  the  O  of  the  air  in  the  bottle. 


SULPHUR. 


107 


with  SO  2  and   excess   of   atmospheric    air.     The  min- 
gled gases  pass  into   immense   chambers,  F,  of  sheet 


Fig.   50. 


■a^_n,^ni n n      lii g| si      a      r^     si     u\ 


lead.  A  shallow  layer  of  HgO,  d,  covers  the  floor, 
and  the  intermixture  and  chemical  action  of  the 
gases  are  further  favored  by  the  injection  of  jets  of 
steam,  c,  supplied  from  the  boiler,  G. 

The  chemical  action  which  ensues  may  be  ex- 
plained as  follows  :— The  nitric  acid  is  quickly  reduced 
to  nitric  oxide,  NO.  This  takes  up  an  atom  of  0 
from  the  air,  becoming  NO2,  and  flies  back  to  the 
SO2  which,  with  a  molecule  of  H2O  becomes  H2SO4, 
a  molecule  of  sulphuric  acid.  The  NO  once  more 
seeks  the  air  and  returns  laden  with  0  for  the  SO  2. 
The  weak  sulphuric  acid  which  collects  on  the  floor 
is  drawn  off  and  condensed  by  evaporation  in  lead 
pans,  and  finally,  when  it  begins  to  corrode  the  lead, 
in  platinum  or  glass   stills.     It  is  then  put  in   large 


108 


INORGANIC     CHEMISTRY. 
Fm.  51. 


Making  H.SO,. 

bottles  packed  in   boxes   called   carboijs,  when   it  is 
ready  for  transportation. 

Properties.  — It  is  a  heavy,  oily  liquid,  without 
odor,  and  when  pure,  colorless.  The  commercial  acid 
is  slightly  colored  by  impurities.  Its  affinity  for 
moisture  is  most  remarkable.,^  If  exposed  in  an  open 
bottle  it  gradually  absorbs  water  from  the  air,  and 
increases  in  bulk,  sometimes  even  doubling  its  weight. 
It  blackens  wood  and  other  organic  substances,  by 
taking  away  their  H  and  0  and  leaving  the  C* 
When  mixed  with  HjO,  it  produces  much  heat;  4 
parts  of  acid  to  1  of  H2O  will  boil  a  test-tube  of 
water.!     It  commonly  contains  lead,  which  falls  as  a 

*  Strouf,'  oil  of  vitriol  poured  on  a  little  loaf-sugar  will  convert  it  into 
black  charcoal.  Sugar  consists  of  C,  H,  and  O,  and  gives  up  the  H  and  O 
to  satisfy  the  acid. 

t  In  mixing  H,SO.  and  H.O,  the  H.SO.  should  always  be  poured  into 
the  HjO  (and  not  the  11,0  into  the  HjSO.)  slowly  and  with  constant  stirring. 


SULPHUR, 


109 


milky  precipitate  (PbS04)  wlien  the  acid  is  diluted. 
It  is  the  strongest  of  the  acids,  and  will  displace  the 
others  from  their  compounds.  It  stains  cloth  red, 
but  the  color  can  be  restored  by  an  alkali,  if  applied 
\mmediately.  Its  test  is  barium  chloride,  which  forms 
a  heavy  white  precipitate.  In  this  way  a  drop  of 
H2SO4  can  be  detected  in  a  quart  of  H2O. 


Fig.  52. 


Preparing   H^S. 

Hydrogen  Sulphide,  HgS,  Sulphuretted  Hydrogen, 
SuIpJii/dric  Ac Kl— This  gas  is  produced  in  the  decay 
of  various  organic  substances,  and  is  always  found 
near  cess-pools,  drains,  and  sinks,  turning  lead  paint 
black  and  emitting  a  disagreeable  smell.  It  gives 
the  characteristic  odor  to  the  mineral  waters  of  Avon, 
Clifton,  Sharon,  and  other  celebrated  sulphur  springs. 
It  is  prepared  by  the  action  of  dilute  H2SO4  upon 
ferrous  sulphide  (FeS).     The   reaction   is   as  follows: 


FeS  +  H2SO4  =  FeS04 


H2S 


110  INORGANIC     CHEMISTRY. 

HgS  lias  the  disgusting  odor  of  rotten  eggs.  It 
burns  with  a  pale  blue  flame,  producing  SO  2  and 
H2O.  It  is  very  poisonous.  The  gas  as  well  as  its 
solution  in  H2O  are  much  used  in  the  analj^tical  labo- 
ratory to  precipitate  many  of  the  metals  as  sulphides. 
Its  test  is  lead  acetate  (sugar  of  lead),  with  which 
it  forms  black  PbS  (lead  sulphide). 

Carbon  Disulphide,  CS2,  is  produced  by  passing 
the  vapor  of  S  over  red-hot  coals.  It  is  a  volatile, 
colorless  liquid.  The  fact  that  a  yellow,  odorless 
solid  thus  unites  with  a  black,  odorless  solid  to  form 
such  a  colorless,  odoriferous  liquid,  illustrates  very 
finely  the  transformations  which  may  be  effected 
by  chemical  affinity.  CS2  readily  dissolves  S,  P, 
and  I.  It  is  largely  used  as  a  solvent  for  caout- 
chouc and  as  a  means  for  recovering  from  wool 
the  oil  and  fats  with  which  they  are  treated.  It  is 
a  powerful  refractor  of  light,  and  is  used  for  filling 
hollow,  glass  prisms  employed  in  experiments  with 
the  solar  spectrum.  In  its  combustion  it  unites  with 
0,  forming  CO  2  and  S02. 


PRACTICAL     QUESTIONS. 

1.  If  chlorine  water  stands  in  the  sunlight  for  a  time,  it  will  only  red- 
den a  litmus-solution.    Why  does  it  not  bleach  it? 

2.  Why  do  tinsmiths  moisten  with  HCl,  or  sal-ammoniac,  the  surface 
of  metals  to  bo  soldered? 

3.  How  much  HCl  can  be  made  from  25  kilos  of  common  salt? 

4.  What  weight  of  NaCl  would  be  required  to  form  25  kilos  of  HCl. 

5.  HCl  of  a  specific  gravity  of  1.2  contains  about  40  per  cent,  of  the 
gas.  This  is  very  strong  commercial  acid.  What  weight  could  be  formed 
by  the  HCl  gas  produced  in  the  reaction  named  in  the  preceding  problem? 

6.  What  is  the  difference  between  sublimation  and  distillation? 

7.  Why  do  eggs  discolor  silver  spoons? 


VALENCE.  Ill 

8.  Explain  the  principle  of  hair-dyes. 

9.  Is  it  safe  to  mix  oil  of  vitriol  and  water  in  a  glass  bottle? 

10.  What  is  the  color  of  a  sulphuric  acid  stain  on   cloth?    How  would 
you  remove  it? 

11.  What   causes  the   milky   look  wheji    oil    of   vitriol   and  water   are 
mixed  ? 

12.  What  is  the  chemical  relation  between  animals  and  plants?    "Which 
perform  the  office  of  reduction,  and  which  of  oxidation? 

13.  How  many  pounds  of  S  are  contained  in  a  cwt.  of  HoSO,  ? 

14.  How  much  O  and  H^O  are  needed  to  change  a  ton  of  SO2  to  H^SOi? 

15.  How  much  O  in  a  pound  of  HjSO,  ? 

16.  State  the  analogy  between  the  compounds  of  O  and  S. 


VALENCE. 

Ix  the  Introduction  it  was  stated  that  atoms  had 
a  certain  property',  in  virtue  of  which  each  could 
hold  a  definite  number  of  other  atoms  in  combina- 
tion, and  that  this  property  was  called  valence. 

If  we  now  review  the  formulas  of  some  of  the 
compounds  with  which  we  have  become  familiar, 
we  shall  be  able  to  see  more  clearly  just  what  is 
meant  by  this  statement.  We  have  had  the  follow- 
ing binary  compounds  of  H  : 

HCl,     H2O,     NH3,     CH4. 

We  see  from  these  that  the  CI,  0,  N,  and  C  atoms 
differ  from  each  other  in  respect  to  the  number  of 
H  atoms  which  they  hold  in  combination ;  0  holds 
twice  as  many  as  CI ;  N  three  times  as  many,  and 
C  four  times  as  many  as  CI  or  twice  as  many  as  0. 
No  atom  can  hold  a  less  number  of  any  other  atoms 
than  CI  or  H.  That  is  to  saj^,  they  have  the  property 
of  valence  in  the  lowest  degree.     On  this  account  CI, 


112  INORGANIC     CHEMISTRY. 

H,  and  other  atoms  which  can  hold  but  one  of  them 
are  called  univalent ;  atoms  which,  like  0,  can  hold 
two  of  H  or  two  unit  atoms  in  combination,  are 
called  bivalent;  atoms  like  N,  which  can  hold  three 
unit  atoms,  are  called  trivalent ;  and  atoms  like  C, 
which  hold  four,  are  called  quadrivalent.  Thus,  F  is 
seen  to  be  univalent  (HF) ;  S,  bivalent  in  HjS  and 
quadrivalent  in  SO 2  (since  each  0  atom  is  equivalent 
to  two  atoms  of   H);    P  trivalent  in    PH3. 

When  the  H  of  acids  is  replaced  by  metals  in 
the  formation  of  salts,  a  univalent  metal  may  take 
the  place  of  each  atom  of  H,  as  in  NaCl,  NaNOs, 
N 82804 ;  or  a  bivalent  metal  may  take  the  place 
of  two  atoms  of  H,  as  in  MriCls,  CU2NO3,  PbS04  ;  and 
so  on. 

Acids  which  contain  but  one  atom  of  replaceable 
H  are  called  monobasic  acids.  Such  acids  can  form 
only  one  kind  of  salt  with  the  same  metal.  Acids 
which  have  two  {bibasic)  or  more  {tribasic,  etc.) 
replaceable  atoms  of  H  can  form  two  or  more  classes 
of  salts,  in  some  of  which  only  a  part  of  the  H  is 
replaced  by  a  metal;  in  others,  all.  Thus,  H2SO4, 
a  bibasic  acid,  forms  Na2S04,  and  NaHS04.  The 
former  is  called  normal  sodium  sulphate,  the  lat- 
ter acid  sodium  sulphate,  because  it  still  contains 
replaceable  H. 


PHOSPHORUS. 


113 


PHOSPHORUS 


Fig.   53. 


Symbol,  P Atomic  Weight,  31 Specific  Gravity,  1.83, 

The  name  Phosphorus  signifies  Ught-hearer,  given 
because  this  substance  glows  in  the  dark.  It  was 
called  by  the  old  alchemists  "the  son  of  Satan."* 

Occurrence. — It  exists  in  combination  with  0  and 
metals  in  a  number  of  minerals  and  rocks,  and   by 
their    decay   passes    into    the    soil,    is    taken    up    by 
plants,  is  then  stored  in  their 
seeds  (wheat,  corn,  oats,  etc.), 
and    finally    passes    into    our 
bodies.    As  calcium  phosphate 
(Ca32P04,   phosphate   of  lime), 
it   is  a  prominent  constituent 
of  our  bones. t    Phosphorus  is 
so  necessary  to  the  operation 
of    the    brain    that    a    saying 
has  become  current,  "Without 
phosphorus,  no  thought."  X 

Preparation. — It  is  prepared  in  considerable  quanti- 

*  The  following  singular  event  is  said  to  have  occuired  many  years 
before  the  reputed  discovery  of  phosphorus  by  Brandt  in  1669.  A  certain 
Prince  San  Severo,  at  Naples,  exposed  some  human  skulls  to  the  action  of 
several  re-agents,  and  then  to  the  heat  of  a  furnace.  From  the  product  he 
obtained  a  substance  which  burned  for  months  without  apparent  loss  of 
weight.  San  Severo  refused  to  divulge  the  process,  as  he  wished  his  family 
vault  to  be  the  only  one  to  possess  a  '■'■  i^rpetttal  lamp,''''  the  secret  of  which 
he  considered  himself  to  have  discovered. 

t  "Of  phosphorus  everj'  adult  person  carries  enough  (1?4  lbs.)  about 
with  him  in  his  body  to  make  at  least  4,000  of  the  ordinary  two-cent 
packages  of  friction  matches,  but  he  does  not  have  quite  sulphur  enough 
to  complete  that  quantity  of  the  little  incendiary  combustibles."— Nichols' 
Fireside  Science. 

X  See  an  article  by  Prof.  Atwater  in  The  Century,  for  June,  1887,  page  249. 


Manufacture  of  Pho/iphorus. 


11-i  INORGANIC     CHEMISTRY. 

ties  from  bones.  These  are  first  calcined  to  white- 
ness to  burn  out  the  animal  matter,  then  treated, 
with  H2SO4,  which  changes  the  calcium  phosphate 
into  a  compound  which  is  reduced  at  a  high  tem- 
perature by  C.  The  phosphorus  which  distils  as  a 
vapor  is  condensed  under  H2O. 

Properties. — It  is  a  waxy,  translucent  solid,  at  all 
temperatures  above  0°C.  emits  a  feeble  light,  melts 
at  44°  C,  and  ignites  at  a  little  higher  temperature. 
It  should  be  handled  with  the  utmost  care,  always 
kept  and  cut  under  HgO,  never  used  except  in  very 
small  quantities,  and  never  held  in  the  hand.  Its 
burns  are  deep  and  dangerous.  It  is  poisonous,  and 
its  vapor  produces  horrible  ulcerations  of  the  jaw- 
bone in  workmen  who  use  it  carelessly. 

Red  Phosphorus. — Heated  for  several  hours  at  a 
temperature  of  about  250°C.,  in  a  close  vessel,  the 
melted  phosphorus  changes  into  a  brick-red  solid, 
and  loses  all  its  former  properties.  It  is  now  insolu- 
ble in  CS2,  which  can  be  used  to  dissolve  out  every 
trace  of  the  common  form.  Its  specific  gravity  is 
increased  to  2.14.  It  can  be  handled  with  impunity, 
carried  in  the  pocket  like  so  much  snuff,  and  even 
heated  to  nearly  260°C.  without  taking  fire.  At  a 
little  over  260°  C,  however,  it  changes  into  the  com- 
mon form  and  bursts  into  a  blaze. 

Uses. — Matches. — The  principal  use  of  phosphorus 
is  in  the  manufacture  of  matches.  1.  The  Lucifer 
Match. — The  bits  of  wood  are  first  dipped  in  melted 
S  and  dried ;  then  in  a  paste  of  phosphorus,  niter, 
and  glue,  which   completes  the   process.    The  object 


PHOSPHORUS.  115 

of  the  niter  is  to  furnish  0  to  quicken  the  combus- 
tion. Instead  of  this,  potassium  chlorate  is  some- 
times used ;  it  can  be  recognized  by  a  crackling 
sound  and  jets  of  flame  when  ignited.  The  tips  are 
colored  by  red-lead,  or  Prussian  blue,  mixed  in  the 
paste.  When  a  match  is  burned,  the  reaction  is  as 
follows :  first,  the  phosphorus  ignited  by  friction 
burns,  forming  P2O5 ;  *  this  produces  heat  enough 
to  inflame  the  S,  which  makes  SO 2 ;  lastly,  the 
wood  takes  fire,  and  forms  CO  2  and  H2O.  Thus  there 
are  four  compounds  produced  in  the  burning  of  a 
single  match. 

2.  The  Safety  Match.  —  The  pieces  of  wood  are 
dipped  into  melted  paraffine  (see  p.  190)  and  dried. 
They  are  then  capped  with  a  paste  of  potassium 
chlorate,  sulphide  of  antimony,  powdered  glass,  and 
gum-water.  They  ignite  only  when  rubbed  on  a  sur- 
face covered  with  a  mixture  of  red  phosphorus  and 
powdered  glass. 

Phosphorescence  is  the  property  of  emitting  light, 
without  the  high  temperature  which  accompanies 
ordinary  burning.  We  have  seen  that  P  glows  in 
the  dark,  but  it  is  by  no  means  the  only  substance 
which  presents  this  phenomenon.  The  luminous  ap- 
pearance of  putrefying  fish  and  decayed  wood  is 
well  known.     The   latter   is   sometimes  called   "fox- 

*  The  buming  phosphorus  produces  a  very  luminous  flame,  because  of 
the  reflection  of  light  from  the  dense  vapor  (PoOs).  The  following  experi- 
ment is  very  suggestive  in  this  connection :  Ignite  a  bit  of  phosphorus 
placed  upon  a  sheet  of  white  paper.  The  paper  will  be  blackened  just 
where  the  phosphorus  lay,  but  will  not  take  fire ;  and  after  the  flame  is 
extinguished,  one  can  write  upon  it  with  pen  and  ink,  close  to  the  edge  of 
the  charred  portion. 


116 


INORGANIC     CHEMISTRY. 


fire."  The  "glow-worm's  fitful  light"  is  associated 
with  our  memory  of  beautiful  summer  evenings.  In 
the  West  Indies,  fire-flies  are  found  that  emit  a  green 
light  when  resting,  and  a  red  one  when  flying.  They 
are  so   brilliant   that   one   will   furnish   light  enough 

Fig.  54. 


Preparation  of  PH^. 


for  reading.  The  natives  wear  them  for  ornaments 
on  their  bonnets,  and  illuminate  their  houses  by 
suspending  them  as  lamps.  The  ocean  occasionally 
takes  on  strange  colors,  and  the  sailor  finds  his  vessel 
plowing  at  one  time  apparently  a  furrow  of  fire,  and 
at  another  one  of  liquid  gold.  The  water  is  all 
aglow,  and  the  flames  seem  to  leap   and  dance  with 


ARSENIC.  117 

the  waves  or  the  motion  of  the  ship.  The  phe- 
nomenon is  produced  by  multitudes  of  animalcules 
which  frequent  certain  seas.* 

Compounds.  —  Hydrogen  Phosphide,  PH3,  Pltos- 
phuretted  Hydrogen,  is  a  poisonous  gas,  remarkable 
for  its  disgusting  odor,  for  igniting  spontaneously 
on  coming  to  the  air,  and  for  the  singular  beauty 
of  the  rings  formed  by  its  smoke.  It  is  prepared  by 
heating  in  a  retort  a  strong  solution  of  potash  con- 
taining a  few  bits  of  phosphorus.  It  has  been 
thought  by  some  that  the  Will-o'-the-wisp,  Jack-o'- 
the-lantern,  etc.,  as  seen  near  grave-yards  and  in 
swampy  places,  are  produced  by  this  gas  coming 
off  from  decaying  substances,  and  igniting  as  it 
reaches  the  air. 


ARSENIC. 
Symbol,  As Atomic  Weight,  75  ...  Specific  Gravity,  5.7. 

Volatilizes  without  fusion  at  about  1*50'  C. 

As  is  a  brittle,   steel-gray  metal, f   commonly  sold, 
when  impure,  as   cohalt.X    If  heated   in   the  open  air 

*  Many  substances,  after  having  been  exposed  to  the  light,  will  shine 
for  some  time  when  removed  into  the  darkness.  Thus,  a  dial  coated  with 
the  so-called  Luminous  Paint  (calcium  sulphide)  wiU  show  the  time  at  night. 

t  Arsenic  very  much  resembles  phosphorus  in  its  general  properties,  and 
is  therefore  classified  with  it,  but  it  conducts  electricity  moderately,  and  has 
a  high  brilliancy.  It  is  intermediate  between  the  non-metals  and  the 
metals. 

X  Cobalt  is  a  reddish-white  metal,  found  in  combination  with  arsenic. 
Co  received  its  name  from  the  miners,  because  its  ore  looked  so  bright  that 
they  thought  they  would  obtain  something  valuable ;  but  when,  by  roast- 


118  INORGANIC     CnEMISTRY. 

it  gives  off  the  odor  of  garlic,  which  is  a  test 
of  As. 

Arsenic  Trioxide,  AS2O3. — This  is  the  well-known 
"ratsbane,"  and  is  sometimes  sold  as  simply  "arsenic," 
or  "white  arsenic," 

Preparation. — It  is  made  in  the  Harz  and  else- 
where, by  roasting  arsenical  ores  at  the  bottom  of  a 
tower,  above  which  is  a  series  of  rooms  through 
which  the  vapors  ascend,  and  pass  out  at  a  chimney 
in  the  top.  The  As  burns,  forming  AS2O3,  which  col- 
lects as  a  white  powder  on  the  walls  and  floors  of 
the  chambers  above.* 

Properties. — "Arsenic"  is  slightly  soluble  in  HgO, 
and  has  a  weak  metallic,  faintly  sweetish  taste.  It 
is  a  powerful  jjoison,  doses  of  two  or  three  grains 
being  fatal,  although  an  over-dose  acts  as  an  emetic. 
It  is  an  antiseptic,  and  so  in  cases  of  poisoning 
frequently  attracts  attention  by  the  preservation 
of   parts  of  the   body  for  a  considerable  time  after 

ing,  it  crumbled  tx)  ashes,  they  believed  themselves  mocked  by  the  evil 
spirit  (Kobolt)  of  the  mines.  The  oxide  of  cobalt  makee  a  beautiful  blue 
glass,  which,  when  ground  fine,  is  called  srnalt.  It  is  used  for  tinting  paper, 
and  by  laundry  women  to  give  the  finished  look  to  cambrics,  linen,  etc. 
Its  impure  oxide,  called  zaffer,  imparts  the  blue  color  to  common  eartlien- 
ware  and  porcelain.  The  chloride  (CoClJ  is  used  as  a  sympathetic  ink. 
Letters  written  with  a  dilute  solution  of  it  are  invisible  when  moist  with 
the  HjO  absorbed  from  the  air,  but  on  being  dried  at  the  stove,  again 
become  blue.  If  the  paper  be  laid  aside  the  writing  will  disappear,  but 
may  be  revived  in  the  same  manner.  A  winter  landscape  may  be  drawn 
with  India-ink,  the  leaves  being  added  with  this  ink.  On  being  brought 
to  the  fire  it  will  bloom  into  the  foliage  of  summer. 

*  Its  removal  is  a  work  of  great  danger.  The  workmen  are  entirely 
enveloped  in  a  leathern  dress  and  a  mask  with  glass  eyes;  they  breathe 
through  a  moistened  sponge,  thus  filtering  the  air  of  the  fine  particles  of 
arsenic  floating  through  it.  Yet,  in  spite  of  all  these  precautions,  they 
rarely  live  beyond  forty. 


ARSENIC. 


119 

The   antidote   is 


the   murder   has   been   committed 
milk  or  white  of  egg* 

Marsh's  Test. — There  is  no  other  poison  which  is 
so  easily  detected.  Prepare  a  flask  for  the  evolution 
of  H,    Ignite  the  jet  of  gas,  and  hold  in  the  flame  a 

Fig.  5.5. 


MarsK's  Test. 

cold  porcelain  dish.  If  it  remains  untarnished,  the 
materials  contain  no  As.  Now  pour  in  through  the 
funnel-tube  a  few  drops  of  a  solution  of  As  ;f  the 
color   of   the   flame  will   be   seen   to   change   almost 

*  The  exact  chemical  antidote  is  hydrated  ferric  oxide.  In  this,  as  in 
most  other  cases  of  poisoning,  where  the  antidote  is  not  at  hand,  an  emetic 
should  be  taken  at  once— a  tea-spoonful  of  mustard  in  a  glass  of  warm 
water,  or  even  a  quantity  of  soap-suds.    (See  "  Physiology,"  page  209.) 

t  This  is  made  by  dissolving  a  little  As^Oa  in  HCl. 


120  INORGANIC     CHEMISTRY. 

instantly,  and  a  copious  deposit  of  As  will  be  formed 
on  the  dish.  If  the  tube  through  which  the  gas  is 
passing  bo  heated  (see  fig.  55),  a  metallic  mirror  of 
arsenic  will  appear  just  beyond  the  heated  place.* 
The  gas  formed  in  this  experiment  —  arseniuretted 
hydrogen — is  very  poisonous  indeed,  and  the  utmost 
care  should  be  used  to  prevent  its  inhalation. 

Arsenic-Eating. — It  is  said  that  the  peasants  in  a 
portion  of  Styria  are  accustomed  to  eat  As,  both  fast- 
ing and  as  a  seasoning  to  their  food.  A  very  minute 
portion  will  warm,  stimulate,  and  aid  in  climbing 
lofty  mountains.  The  arsenic-eaters  are  described  as 
plump  and  rosy,  and  it  is  said  that  the  young  people 
resort  to  this  dangerous  substance,  as  a  species  of 
cosmetic.  They  begin  with  small  doses,  which  are 
gradually  increased ;  but  if  the  person  ceases  the 
practice,  all  the  symptoms  of  arsenic  poisoning  im- 
mediately appear.  Horse-jockeys  sometimes  feed 
arsenic  to  their  horses  to  improve  their  tlesh  and 
speed. 


BORON. 

Symbol,   B /^lomic  Weigl^l,   II, 

Boron    is   found    in    nature    in    combination  with 
H  and  0  as  boric  acid,  and  as  borates.    Boric  acid  is 

*  In  a  case  of  poisoning  the  contents  of  tlie  stomach  would,  of  course, 
be  substituted  for  the  solution  of  As,  the  organic  matter  first  being  de- 
stroyed, and  other  tests  besides  these  would  be  employed.  We  can  imagine 
with  what  care  a  chemist  would  conduct  the  examination,  and  \s'ith  what 
intense  anxiety  he  would  watch  the  porcelain  dish  as  the  flame  played 
upon  it,  hesitating,  and  dreading  the  issue,  as  he  felt  the  life  of  a  fellow- 
being  trembling  on  the  result  of  his  experiment. 


BORON, 


121 


abundant  in  the  volcanic  districts  of  Tuscany.* 
Along  the  sides  of  the  mountains,  series  of  basins 
are  excavated  and  filled  with  cold  water  from  the 
neighboring  springs.  Into  these  basins  the  jets  of 
steam,  charged  with  boric  acid,  are  conducted.  The 
H2O  absorbs  the  acid,  and  itself  becomes  heated  to 
the  boiling-point.    It  is  then  drawn  off  into  the  next 

Fig.  56. 


Preparing  Bone  Acid  in  Thibet. 


lower  basin.  This  process  is  continued  until  the 
bottom  one  is  reached,  when  the  solution  runs  into 
leaden  pans  heated  by  the  steam  from  the  earth; 
here  the  H2O  is  evaporated,  and  the  boric  acid  col- 
lected. 

Borax  (NasB^Oy,  IOH2O)  is  a  salt  of  this  acid.     It 
is    a    natural    production,  formerly  obtained    by  the 

*  Throughout  an  area  of  nearly  thirty  miles,  is  a  wild,  mountainous 
region,  of  terrible  violence  and  confusion.  The  surface  is  ragged  and  blasted. 
Every-where  there  issue  from  the  ground  jets  of  steam,  filling  the  air 
with  offensive  odors.  The  earth  itself  shakes  beneath  the  feet,  and  fre- 
quently yields  to  the  tread,  ingulfing  man  and  beast.  "The  waters  below 
are  heard  boiling  with  strange  noises,  and  are  seen  breaking  out  upon  the 
surface.  Of  old,  it  was  regarded  as  the  entrance  to  hell.  The  peasants  pass 
by  in  terror,  counting  their  beads  and  imploring  the  protection  of  the 
Virgin." 


122  INORGANIC     CHEMISTRY. 

drying  of  certain  lakes  in  Thibet,  but  since  found 
abundantly  in  California  and  Nevada.  When  dis- 
solved in  alcohol,  boric  acid  gives  to  the  flame  a 
peculiar  green  tint.  This  is  an  easy  test  of  the  pres- 
ence of  this  acid.  In  order  to  make  this  test  with 
borax,  H2SO4  must  be  added  to  set  the  boric  acid 
free,  for  the  salts  of  boric  acid  do  not  color  the 
flame.  The  salt  is  employed  in  welding.  It  dissolves 
the  oxide  of  the  metal,  and  keeps  the  surface  bright 
for  soldering.  It  has  mild  cleansing  properties  due 
to  its  power  of  dissolving  oils  and  resinous  substances 
and  is  used  in  washing.* 


SILICON. 

Symbol,  Si ....  Atomic  Weight,  28.. ..  Specific  Gravity,  2.49, 

Occurrence. — Silicon  is  found  in  combination  with 
0  as  silica  (silicic  anhydride,  SiOg),  commonly  called 
silex  or  quartz.  So  abundant  is  this  oxide  that  it 
probably  comprises  nearly  one  half  of  the  earth's 
crust.  (See  "Geology,"  p.  40.)  It  forms  beautiful 
crystals  and  some  of  the  most  precious  gems.  When 
pure,   it    is    transparent    and    colorless,   as    in    rock 

*  Borax  is  extensively  used  in  "  blow- pipe  analysis."  When  melted  with 
chromium  oxide,  it  gives  an  emerald  green ;  with  cobalt  oxide,  a  deep  blue ; 
with  copper  oxide,  a  pale  green ;  and  with  manganese  oxide,  a  violet.— The 
Salt,  or  Alkali,  Marshes  of  Nevada,  contain  extensive  deposits  of  sodium 
chloride,  sodium  carbonate,  sodium  borate,  calcium  borate,  etc.  There  are 
hundreds  of  acres  covered  to  a  depth  of  neai-ly  two  feet  with  crude,  semi- 
crystalline  borax.  See  an  article  entitled  "  Borax  in  America,"  in  the 
Popular  Science  Monthly,  July,  1 882. 


SILICON.  123 

crystal.  Jasper,  amethyst,  agate,  chalcedony,  blood- 
stone, chrysoprase,  sardonyx,  etc.,  are  all  common 
flint-stone  or  quartz,  colored  with  some  metallic 
oxide.  The  opal  is  only  Si02  and  HjO.  Sand  is 
mainly  fine  quartz,  which,  when  hardened  and  ce- 
mented, we  call  sandstone.  Yellow  or  red  sand  is 
colored  by  iron-rust. 

Properties  of  SiOa- — It  is  tasteless,  odorless,  and 
colorless.'  It  seems  very  strange  to  call  such  an  inert 
substance  an  anhydride  ;  yet  it  unites  with  the  al- 
kalies, neutralizes  their  properties,  and  forms  a  large 
class  of  salts  known  as  the  silicates,  which  are  found 
in  the  most  common  rocks. — Example:  feldspar, 
found  in  granite. 

Silica  in  Soil  and  Plants. — Silica  is  insoluble  in 
H2O,  unless  it  contains  some  alkali.  When  the  sili- 
cates, so  abundant  in  rocks,  disintegrate  and  form 
soil,  the  alkali  and  silica  are  both  dissolved  in  the 
water,  and  taken  up  by  the  roots  of  plants.  We  see 
the  silex  on  the  surface  of  scouring-rushes  and 
sword-grass,  which  cut  the  fingers  if  handled  care- 
lessly. It  gives  stiffness  to  the  stalks  of  wheat  and 
other  grains,  and  produces  the  hard,  shiny  surface  of 
bamboo,  corn,  etc. 

Petrifaction. — Certain  springs  contain  large  quan- 
tities of  some  alkaline  carbonate ;  their  waters,  there- 
fore, dissolve  silica  abundantl}^  If  we  place  a  bit  of 
wood  in  them,  as  fast  as  it  decays,  particles  of  silica 
will  take  its  place  and  thus  petrify  the  wood.  The 
wood  has  not  been  changed  to  stone,  but  has  been 
replaced  by  stone. 


124  INORGANIC     CHEMISTRY. 

Compounds.— The  Silicates. — Glass*  is  a  mixture 
of  several  silicates.  There  are  four  varieties  used  in 
the  arts.  1.  Window  or  plate  glass  is  composed  of 
silicates  of  calcium  and  sodium.  It  is  made  by  heat- 
ing white  sand,  sal-soda,  and  lime  in  clay  crucibles 
for  about  forty-eight  hours,  when  the  materials  fuse 
and  combine  into  a  double  silicate.  The  Ca  hardens 
and  gives  luster;    the    Na   renders  the   glass  fusible. 

2.  Bohemian  glass  consists  of  silicates  of  calcium 
and  potassium.  It  can  withstand  a  very  high  tem- 
perature without  softening,  and  resists  chemical  ac- 
tion ;   hence  it  is  of  great  importance  to  the  chemist. 

3.  Flint-glass  \  or  crystal  contains  silicates  of  potas- 
sium and  lead.  The  latter  is  used  in  large  quantities 
and  produces  a  soft,  lustrous  glass,  which  can  be 
ground  into  imitation  gems,  tableware,  chandelier 
pendants,  prisms,  etc.  4.  Oi^een  bottle-glass  is  made 
of  silicates  of  calcium,  sodium,  aluminium,  and  iron. 
The  last  gives  the  opaque  green  of  the  common  junk 
bottle. 

*  Glass  was  known  to  the  ancients.  Hieroglyphics,  that  are  older  than 
the  sojourn  of  the  Lsraelites  in  Egypt,  represent  glass-blowers  at  work, 
much  after  the  fashion  of  the  present.  In  the  ruins  of  Nineveh,  articles 
of  glass,  such  as  vases,  bowls,  etc.,  have  been  discovered.  Mummies,  three 
thousand  years  old,  are  adorned  vrith  glass  beads.  The  inventor  is  not 
known.  Pliny  tells  us  that  some  merchants,  once  encamping  on  the  sea- 
shore, found  in  the  remains  of  their  fire  bits  of  glass,  formed  from  the 
sand  and  ashes  of  the  sea-weed  by  the  heat;  but  this  is  impossible,  as  an 
open  fire  is  not  suflfieiont  to  melt  these  materials.  In  the  fourth  century 
B.C.,  the  glass-works  at  Alexandria  produced  exquisite  ornaments,  with 
raised  figures  beautifully  cut  and  gilded.  But  in  the  twelfth  centur.v  a.d., 
glass  was  still  so  costly  in  England  that  glass  windows  were  thought  very 
magnificent ;  and,  as  late  even  as  about  1500,  when  the  great  Earl  of  North- 
umberland left  one  of  his  houses  for  a  time,  he  was  careful  to  have  the 
glass  of  the  windows  taken  down  and  packed  for  safe-keeping. 

t  So  called  because  pulverized  flint  was  formerly  used  for  sand. 


SILICON.  125 

Coloring  Glass. — A  small  quantity  of  some  metal- 
lic oxide  melted  with  the  glass  furnishes  any  tint 
desired :  Co  gives  a  beautiful  sapphire  blue  ;  Au  or  Cu, 
a  ruby-red;  Mn,  a  violet;  U,  a  yellow;  As,  a  soft  white 
enamel,  as  in  lamp-shades ;  and  Sn,  a  hard  enamel, 
as  in  watch-faces. 

Annealing  Glass, — If  the  glass  utensils  were  cooled 
immediately,  they  would  be  found  extremely  brittle, 
and  would  drop  to  pieces  in  the  most  unaccountable 
way.  The  heat  of  the  hand  or  a  draft  of  cool  air 
would  sometimes  crack  off  the  thick  bottom  of  a 
tumbler.  They  are  therefore  cooled  very  gradually 
for  days,  which  allows  the  particles  to  assume  their 
natural  place,  and  the  molecular  attractions  to  be- 
come equalized.* 

Ornamental  Ware.  —  Venetian  balls  or  paper 
weights  are  made  bj^  arranging  bits  of  colored  glass 
in  the  form  of  fruits,  flowers,  etc.,  and  then,  insert- 
ing them  in  a  hollow  globe  of  transparent  glass,  still 
hot,  the  workman  draws  in  his  breath,  and  the 
pressure  of  the  air  above  collapses  the  globe  upon 
the  colored  glass,  and  leaves  a  concave  surface  in 
the  opposite  side  of  the  weight.  The  lens  form 
always  magnifies  the  size  of  the  figures  within. 

Tubes  and  Beads. — In  making  glass  tubing,  the 
workman  inserts  his  iron  blowing-tube  in  a  pot  of 
melted  glass,  and  gathers  upon  the  end  a  suitable 
amount;  drawing  this  out,  he  blows  into  the  tube, 
swelling   the    glass   into    a   globular   form.      Another 

*  This  principle  is  beavitifully  illustrated  by  the  toy  known  as  the 
"Prince  Rupert's  Drop."    (See  "Physics,"  p.  46.) 


126  INORGANIC     CHEMISTRY. 

dip  into  the  pot  and  another  blow  increase  its  size, 
until  at  last  a  second  workman  attaches  an  iron  rod 
to  the  other  end.  The  two  men  then  separate  at  a 
rapid  pace.  The  soft  glass  globe  diminishes  in  size 
as  it  lengthens,  until  at  last  it  hangs  between  them 
a  glass  tube  of  a  hundred  feet  in  length,  and  perhaps 
only  a  quarter  of  an  inch  in  diameter. 

For  making  beads,  glass  tubes  are  cut  in  short 
pieces,  and  then  worked  about  in  a  mixture  of  wet 
ashes  and  sand,  until  they  are  filled.  They  are  next 
put  with  loose  sand  in  a  cylinder  rapidly  revolving 
over  a  hot  furnace.  The  heat  softens  the  glass,  but 
the  mixture  within  presses  out  the  sides,  and  the 
sand  grinds  the  edges,  until  at  last  the  beads  become 
round  and  perfect,  and  are  taken  out  ready  for 
market. 


THE    METALS. 


THE  METALS  OF  THE  ALKALIES 

K,  Na,  Li,  Rb,  Cs. 


POTASSIUM 
Synjbol,  K.  .  .  .  Atonjic  Weigljt,  39.1.  .  .  .Specific   Gravity,  0.87. 

Source. — K  occurs  widely  distributed  in  various 
rocks,  which  by  their  decomposition  furnish  it  to  the 
plants.*  When  these  are  burned  it  remains  as  potas- 
sium carbonate  in  the  ashes.  It  also  is  found  in 
considerable  deposits  in  the  form  of  chloride  and 
nitrate. 

Preparation. — This  metal  was  discovered  by  Sir 
Humphrj^  Davy,  in  1807.  On  passing  the  current 
of  a  powerful  electric  battery  through  potash,  the 
globules  of  the  K  appeared  at  the  negative  pole. 
The  metals  Na,  Ba,  Sr,  and  Ca,  were  afterward  sepa- 
rated in  the  same  manner.  This  discovery  constituted 
a    most    important    epoch    in    chemistry.     K    is    now 

*  "  An  acre  of  wheat,  producing  twenty-five  bushels  of  grain  and  3,000 
lbs.  of  straw,  removes  about  40  lbs.  of  potash  in  the  crop.  An  acre  of  com, 
producing  100  bushels,  removes  in  kernel  and  stalk  150  lbs.  of  potash  and 
80  lbs.  of  phosphoric  acid.  An  acre  of  potatoes,  shielding  300  bushels,  will 
remove  in  tubers  and  tops  400  lbs.  of  potash  and  150  lbs.  of  phosphoric 
acid.  A  pound  of  wheat  holds  a  quarter  of  an  ounce  of  mineral  sub- 
stances, and  a  pound  of  potatoes  one  eighth  of  an  ounce," — ^Nichols. 


128  INORGANIC     CHEMISTRY. 

prepared  by  decomposing  potassium  carbonate  by 
means  of  charcoal  in  iron  bottles,  at  an  intense  heat. 
The  green  vapors  of  K  distil  and  are  condensed  in 
receivers  of  naphtha,  and  CO  passes  off  as  a  gas, 
K2C03  +  2C  =  2K  +  3CO,  It  is  a  difficult  and  dangerous 
process.  The  vapor  takes  fire  instantly  on  contact 
with  air  or  water.  It  also  absorbs  CO,  and  the  com- 
pound, if  kept,  becomes  powerfully  explosive.  To 
prevent  this  danger,  the  K  is  immediately  redistilled. 

Properties. — K  is  a  silvery  -  white  metal,  soft 
enough  to  be  spread  with  a  knife,  and  light  enough 
to  float  like  cork.  Its  affinity  for  0  is  so  great  that 
it  is  always  kept  under  the  surface  of  naphtha, 
which  contains  no  0.  K,  when  thrown  on  H2O,  de- 
composes it  with  great  energy  (see  page  38). 

Compounds. — Potassium  oxide,  KjO,  has  so  great 
an  affinity  for  H2O  that  the  anhydrous  form  is  rarely 
prepared.  Its  hydrate,  potassium  hydroxide,  KOH,*  is 
a  white  solid  made  from  potassium  carbonate  by  the 
action  of  slaked  lime.  It  is  the  most  powerful  alkali. 
It  neutralizes  the  acids,  and  turns  red  litmus  to  blue. 
It  is  used  to  cauterize  the  flesh,  and  is  hence  com- 
monly called  "  caustic  potash."  It  dissolves  the  cuticle 
of  the  finger  which  touches  it,  and  so  has  an  unctuous 
feel.  It  unites  with  grease,  forming  soft-soap,  in  the 
manufacture  of  which  it  is  extensively  used. 

Potassium  Carbonate,  KoCOg,  Pearlash,  "  Carbonate 
of  Potash,''  is  obtained  in  the  following  manner: 
Potash  exists  in  plants,  combined  with  various  acids, 
such  as  tartaric,  malic,  oxalic,  etc.     When   the   wood 

*  KjO  +  HjO^^KOH,  or  2  molecules  of  potassium  hydroxide. 


POTASSIUM.  12  9 

is  burned,  the  organic  salts  are  decomposed  by  the 
neat,  and  K  remains  chiefly  as  K2CO3.  The  ashes  are 
then  leached  and  the  lye  is  evaporated,  when  the 
K2CO3  crystallizes.  This  forms  the  "potash"  of  com- 
merce. When  refined,  it  is  called  "pearlash." 
Where  wood  is  abundant,  immense  quantities  are 
burned  solely  for  this  product.* 

Large  quantities  of  potash  are  also  obtained  from 
potassium  chloride  and  sulphate,  by  a  process  which  is 
exactly  like  that  described  on  p.  135  for  making  soda. 
A  considerable  amount  is  also  obtained  from  wool  fat 
and  from  the  waste  in  beet  sugar  manufacture. 

Acid  Potassium  Carbonate,  \  HKCO3,  SaleroAus, 
^^Bicarbonate  of  Potash,'''  is  prepared  by  passing  CO2 
through  a  strong  solution  of  potassium  carbonate. 

Potassium  Nitrate,  KNO3,  Nitrate  of  Potash,  Salt- 
peter^ Niter. — This  salt  is  found  as  an  efflorescence 
on  the  soil  in  tropical  regions,  especially  in  India.  It 
is  obtained   thence  by  leaching. J    It  is  formed  arti- 

*  Vast  deposits  of  potassium  salts  have  been  opened  up  to  us  at  the 
Stassfurth  salt  mines  in  Germany,  the  supply  from  which  is  more  than 
from  the  wood-ash  sources  of  the  whole  world.  "  Only  about  13,000  tons 
of  potash  were  sent  to  market  from  the  United  States  and  British  America 
in  1870,  and  yet  from  Stassfurth,  where  a  dozen  years  ago  it  was  not  sup- 
posed that  a  single  ton  could  be  produced,  30,000  tons  of  potassium  chloride 
were  manufactured  and  supplied  to  consumers  upon  both  continents  during 
the  following  year.  The  surface  salts  at  these  mines,  which  hold  the 
potash,  are  practically  inexhaustible,  and  millions  of  tons  will  be  supplied 
in  succeeding  years." — Fireside  Science. 

t  The  molecule  of  carbonic  acid  is  H0CO3.  In  potassium  carbonate, 
KjCOa,  both  the  atoms  of  H  contained  in  the  carbonic  acid  are  replaced  by 
the  metal  K  ;  in  hydrogen  potassium  carbonate,  HKCO3,  only  one  atom  of 
H  is  thus  replaced. 

t  It  was  manufactured  in  the  Mammoth  Cave,  Kentucky,  during  the 
war  of  1812.  The  remains  of  the  works,  and  even  the  deep  ruts  of  the 
wagon-wheels,  are  still  to  be  seen,  preserved  in  the  pure,  still  air. 


130  INORGANIC     CHEMISTRY. 

ficially  by  piling  up  great  heaps  of  mortar,  refuse  of 
sinks,  stables,  etc.  "In  about  three  years,  these  are 
washed,  and  each  cubic  foot  of  the  mixture  will  fur- 
nish four  or  five  ounces  of  saltpeter."  It  dissolves 
in  about  three  and  a  half  times  its  weight  of  cold 
H2O. 

Properties  and  Uses.  —  It  is  cooling  and  anti- 
septic ;  hence  it  is  used  with  common  salt  (NaCl)  for 
preserving  meat.  It  parts  readily  with  its  0,  of 
which  it  contains  nearly  48  per  cent.,  and  defla- 
grates with  charcoal  brilliantly.  Every  government 
keeps  a  large  supply  on  hand  for  making  gunpow- 
der, in  the  event  of  war.  Gunpowder  is  now  com- 
posed of  about  six  parts,  by  weight,  of  niter,  and  one 
each  of  charcoal  and  sulphur — the  proportion  vary- 
ing with  the  purpose  for  and  the  country  in  which 
it  is  made.  Its  explosive  force  is  due  to  the  expan- 
sive power  of  the  gases  formed.  At  the  touch  of  a 
spark  the  saltpeter  gives  up  its  0  to  burn  the  S  and 
C.  The  reaction  that  ensues  may  be  approximately 
represented  as  follows  :  2KN03  +  S  +  3C=K2S+N2  + 
3CO2. 

Besides  N  and  CO2,  smaller  quantities  of  other 
gases  are  formed,  which,  with  the  sudden  increase  of 
temperature  (to  about  2,200°C.),  expand  till  they  oc- 
cupy at  least  1,500  times  the  space  of  the  powder. 
The  bad  odor  of  Imrnt  powder  is  due  to  the  slow 
formation  of  HjS  in  the  residuum.  Fire-works  are 
composed  of  gunpowder  ground  with  additional  C 
and  S,  and  some  coloring  matter.  Zinc  filings  pro- 
duce   green    stars ;     steel    filings,    variegated    ones. 


SODIUM.  131 

Sr2N03  tinges  flame  with  crimson;  Ba2N03  with 
green.  Sahs  of  copper  give  a  bhie,  and  camphor  a 
pure  white  flame. 

Potassium  Chlorate,  KCIO3,  is  a  white,  crystallized 
salt  much  used  in  preparing  oxygen,  making 
matches,  fire-works,  etc.  It  is  a  powerful  oxidizing 
agent.* 

Potassium  Bichromate,  f  KgCrgOy,  is  a  red  salt 
highly  valued  in  dyeing,  calico-printing,  and  photo- 
lithography. If  we  mix  a  solution  of  this  salt  and 
one  of  sugar  of  lead,  a  yellow-colored  precipitate  will 
be  formed,  known  in  the  arts  as  chrome-yellow  (lead 
chromate).  KaCraOy  is  a  strong  oxidizing  agent,  be- 
ing readily  reduced  in  an  acid  solution  to  a  salt  of  Cr. 


SODIUM. 

Synjbol,  Na.  .  ,  .  Atonjic  Weig))t,  23.  .  .  .  Specific  Gravity,  0.972, 

This  metal  is  found  principally  in   common  salt. 
Its  preparation  is  similar  to  that  of  K,  but  is  more 


*  Examples:  1.  Put  in  a  porcelain  crucible  as  much  KCIO3  as  will  lie  on 
the  point  of  a  knife-blade,  and  half  as  much  S.  On  grinding  with  the  jos- 
tle, rapid  detonations  will  ensue.  2.  Place  in  a  wine-glass  five  or  six  pieces 
of  phosphorus  as  large  as  a  grain  of  wheat,  and  cover  with  crystals  of 
KCIO3.  Fill  the  glass  two  thirds  full  of  HjO.  By  means  of  a  pipette,  or  a 
glass  funnel,  introduce  into  immediate  contact  with  the  KCIO3  a  few  drops 
of  strong  Hi  SO  4.  A  violent  chemical  action  will  immediately  occur,  and 
the  phosphorus  will  bum  under  the  water  with  vivid  flashes  of  light. 

+  Chromic  anhydride  (CrjOj)  is  an  oxide  of  chromium  {chroma,  color),  a 
metal  prized  only  for  its  numerous  brilliantly  colored  compounds.  It  is 
rather  rare,  and  mainly  found  in  chrome  iron-stone  (PeO-Cr^Oa). 


132  INORGANIC     CHEMISTRY. 

easily  managed.  It  is  very  like  K  in  appearance, 
properties,  and  reaction.  It  decomposes  water  ener- 
getically, but  does  not  take  fire  like  the  K,  unless 
the  water  is  warm.  The  test  of  all  the  soda  salts  is 
the  yellow  tint  which  they  give  to  flame. 

Compounds.  —  Sodium  Chloride,  NaCl,  Common 
Salt,  is  a  mineral  substance  absolutely  necessary  to 
the  life  of  human  beings  and  the  higher  orders  of 
animals.  It  does  not  enter  into  the  composition  of 
tissue,  but  is  essential  to  the  proper  digestion  of  the 
food,  and  to  the  removal  of  worn-out  matter,  (See 
"Physiology,"  p.  137.)  It  is  used  extensively  in  the 
preservation  of  foods  and  in  the  manufacture  of 
many  substances.  As  salt  is  so  universally  necessary, 
it  is  found  everywhere.  Our  Father  in  fitting  up  a 
home  for  us,  did  not  forget  to  provide  for  all  our 
wants.  The  quantity  of  salt  in  the  ocean  is  said  to 
be  equal  to  five  times  the  mass  of  the  Alps.  Salt 
lakes  are  scattered  here  and  there.;  saline  springs 
abound;  and  besides  these,  in  the  earth  are  stored 
great  mines,  probably  produced  by  the  evaporation 
of  salt  lakes  in  some  ancient  period  of  the  earth's 
history.  Near  Cracow,  Poland,  are  the  remarkable 
salt  mines  of  Wieliczka,  which  have  been  quarried 
out  of  a  bed  calculated  to  be  five  hundred  miles  long, 
twenty  miles  wide,  and  nearly  a  quarter  of  a  mile 
thick.  In  Spain,  and  lately  in  Idaho,  it  has  been 
quarried  out  in  perfect  cubes,  transparent  as  glass, 
so  that  a  person  can  read  through  a  large  block. 

Preparation. —  On  the  sea-shore  it  is  manufactured 
by  the  evaporation  of  sea-water,  each  gallon  contain- 


SODIUM. 


133 


ing  about  four  ounces.*  At  Syracuse,  New  York, 
near  by  and  underneath  the  Onondaga  Lake,  is  ap- 
parently a  great  basin  of  salt-water,  separated  from 
the  fresh-water  above  by  an  impervious  bed  of  clay. 
Upon  boring  through  this,  the  saline  water  is 
pumped  up  in  immense  quantities.  The  H2O  is 
evaporated  by  heating  in  large  iron  kettles  over  a 
fire,  or  in  shallow,  wooden  vats   by  exposure  to  the 

Fig.  57. 


Hoiyper  form  of  salt  crystals, 

sun — whence  the  name  "solar  salt."  If  boiled  down 
rapidly,  fine  table-salt  is  made ;  if  more  slowly, 
coarse  salt,  as  large  crystals  have  time  to  form. 
Frequently  they  assume  a  "hopper  shape,"  one  cube 
appearing,  then  others  collecting  at  its  edges,  and 
gradually  settling,  until  a  hollow  pyramid  of  salt- 
cubes,  with  its  apex  downward,  is  formed. 

*  "Salt  is  soluble  in  less  than  three  times  its  weight  of  H,0.  It  is 
scarcely  more  soluble  in  hot  than  cold  HjO,  and  a  saturated  solution  (one 
containing  all  it  will  dissolve)  has  about  36  per  cent.  Sea-water  contains 
about  3  per  cent.  Sodium  carbonate  was  formerly  obtained  from  the  ashes 
of  sea-plants,  as  potassium  carbonate  is  now  from  the  ashes  of  land-plants." 

— ROSCOE. 


134  INORGANIC     CHEMISTRY. 

Uses. — NaCI  is  used  largely  in  food,  for  preserv- 
ing meats  and  fish,  and  for  preparing  CI,  HCI,  and 
the  various  compounds  of  Na. 

Sodium  Hydroxide,  Caustic  Soda,  NaOH,  is  pre- 
pared from  sodium  carbonate  by  the  action  of  milk 
of  lime : 

Na2C03  +  Ca(OH)2  =  CaC03  +  2NaOH. 

It  resembles  KOH,  but  is  less  powerful  in  its 
chemical  action.  It  is  largely  used  in  soap-making, 
and  other  technical  operations. 

Sodium  Sulphate  (Na2S04,  lOHgO),  Glauber's  Salt, 
named  from  its  discoverer,  is  made  in  great  quanti- 
ties from  NaCl,  as  the  first  stage  in  the  manufacture 
of  sodium  carbonate.  It  is  remarkably  efflorescent, 
the  salt,  by  exposure  to  the  air,  losing  its  ten 
molecules  of  H2O.*  It  has  a  bitter,  saline  taste,  and 
is  used  in  medicine. 

Sodium  Carbonate  (NasCOg,  IOH2O),  Sal-soda,  is 
used  extensively  in  the  arts.  It  is,  therefore,  of  great 
importance  to  all  consumers  of  soap,  glass,  etc.,  that 
,  it  should  be  manufactured  as  cheaply  as  possible. 
Leblanc's  process  of  making  it  from  NaCI  is  the  most 
important    method.      The    operation    comprises    two 

*  Experiment :  Make  a  saturated  solution  of  sodium  sulphate  in  warm 
water,  and  with  it  fill  a  bottle.  Stuff  cotton  loosely  into  the  neck  of  the 
bottle,  and  let  it  stand.  The  salt  will  remain  for  months  without  crystal- 
lizing ;  but  if  it  be  taken  up,  and  shaken  ever  so  little,  the  whole  mass  will 
instantly  form  into  crystals,  so  filling  the  bottle  that  not  a  drop  of  water 
will  escape,  even  If  it  be  inverted.  Should  there  be  any  hesitation  in 
crystallizing  at  the  moment,  drop  into  the  bottle  a  minute  crystal  of  the 
salt,  and  the  efifect  will  instantly  be  seen  in  the  dartii.g  of  new  crystals  in 
every  direction. 


SODIUM.  135 

stages:  Changing,  1.  NaCl  into  N 32804. ;  and,  2.  NagSO^ 
into  NaaCOs. 

1.  A  mixture  of  NaCl  and  H2SO4  is  heated. 
Na2S04  is  formed  with  a  copious  evolution  of  HCl. 
The  fumes  of  this  gas  are  conducted  into  the  bottom 
of  a  vertical  flue  filled  with  pieces  of  coke  wet  with 
constantly  falling  HgO.  The  gas  is  here  absorbed, 
and  a  weak  muriatic  acid  formed  in  great  quantities.* 

2.  The  NasSO^.  is  heated  with  chalk  (CaCOs)  and  char- 
coal. The  C  deoxidizes  the  N 32804,  changing  it  into 
Na2S.  The  metals  of  the  Na2S  and  the  CaCOa  change 
places,  forming  Na2C03  and  CaS.  Out  of  this  mass, 
called  from  its  color  "  black-ash,"  the  NasCOs  is  dis- 
solved,! and  then  evaporated  to  dryness,  making  the 
"soda-ash"  of  commerce. 

Hydrogen  Sodium  Carbonate  (HNaCOs),  ''Bicar- 
bonate of  Soda,''  is  the  "soda"  of  the  kitchen.  It  is 
prepared  by  the  action  of  CO2  on  sodium  carbonate. 
The  CO2  may  be  easily  liberated  by  the  action  of 
an  acid.     (See  p.  244.) 

Sodium  Nitrate,  NaNOg,  occurs  in  large  deposits  as 
Chili  Saltpeter.  It  attracts  moisture  from  the  air, 
and  so  can  not  supersede  KNO3  in  the  manufacture 
of  gunpowder.    It  is  used  in  making  nitric  acid. 

*  This  acid  was  formerly  allowed  to  escape,  causing  the  destruction  of 
all  vegetation  in  the  neighborhood.  It  is  now,  however,  absorbed  so  per- 
fectly that  the  gases  which  escape  from  the  top  of  the  chimney  will  not 
render  turbid  a  solution  of  silver  nitrate  (see  page  97),  showing  that  there 
is  not  a  trace  of  the  acid  left. 

t  The  insoluble  residuum  of  CaS,  and  the  superfluous  coal,  form  around 
the  alkali  works  a  mountain  of  waste.  Attempts  have  been  made  to  ex- 
tract the  S,  and  at  the  Paris  Exposition  large  blocks  thus  obtained  were 
exhibited. 


136  INORGANIC    CIIKMISTRY. 

AMMONIUM. 

Symbol,  NH^. 

This  is  a  compound  which  has  never  been  sep- 
arated, but  it  is  generally  thought  to  be  the  base  of 
the  salts  formed  by  the  action  of  the  acids  upon  the 
alkali  ammonia,  which  closely  resemble  the  corre- 
sponding salts  of  K.  The  analogy  between  it  and  the 
simple  metals  is  so  very  striking  *  that  it  is  considered 
a  compound  metal,  acting  the  part  of  a  simple  one, 
as  Cy  does  that  of  a  compound  halogen  (see  p.  74), 
All  attempts  to  separate  this  compound  ammonium 
base  from  the  ammonium  salts  result  in  NH3. 

Compounds.  —  Ammonium  Chloride,  NH4CI,  Sal- 
ami/ioniac,  is  prepared  from  the  ammoniacal  liquor 
of  the  gas-works.  (See  p.  73.)  It  is  obtained  either 
as  a  fine  crystalline  meal,  called  "  flowers  of  sal-ammo- 
niac"; as  a  tough,  fibrous,  semi-transparent,  crystal- 
line mass;  or  as  a  fine  powder.  In  no  form  does  it 
reveal  any  trace  of  the  pungent  ammonia,  yet  this 
can  easily  be  set  free,  and  as  we  have  already  seen 
(p.  35).  Sal-ammoniac  is  soluble  in  HgO,  and  when 
dissolved  in  water  causes  a  marked  reduction  in  the 
temperature.  It  has  neither  color  nor  odor,  but  has 
a  very  saline  taste.  It  is  used  in  medicine,  in  the 
preparation  of  NH3  and  the  salts  of   NH4,  in  dyeing, 

*  WTien  NH3  is  dissolved  in  H^O,  forming  NH3IIOII  the  compound  may 
be  represented  as  (NH4)  OH.  Comparing  this  with  the  formula  for  caustic 
potash,  KOH,  we  see  that  the  group  of  elements  NH.  corresponds  to  the 
K.  Thus  we  may  call  a  solution  of  NH,,  ammonium  hydroxide  or  "  caustic 
ammonia,"  as  one  of  potash  is  a  potassium  hydroxide  or  "caustic  potash." 
Both  act  as  powerful  bases,  neutralize  the  acids  and  form  soaps. 


AMMONIUM.  137 

and  also  in  soldering,  as  it  dissolves  the  coating  of 
the  oxide  of  the  metal  and  preserves  the  surfaces 
clear  for  the  action  of  the  solder.  It  is  also  much 
used  now  in  certain  electric  batteries. 

Ammonium  Carbonate,  Sal-volatile,  Smelling  Salts, 
is  prepared  by  the  action  of  chalk  upon  sal-ammo- 
niac. It  is  a  sesquicarbonate,  but  by  the  constant 
loss  of  NH3  it  becomes  crusted  with  a  spongy  coat 
of  the  "bicarbonate,"  hydrogen  ammonium  carbon- 
ate (NH4)HC03.  It  is  largely  used  by  bakers  in 
raising  cake.     (See  p.  245). 

Ammonium  Nitrate  (NH4NO3)  may  be  readily 
formed  by  cautiously  adding  dilute  HNO3  to  aqua 
ammonia  until  the  liquid  becomes  neutral,  and  then 
evaporating.  Long,  needle-shaped  crystals  will  form. 
Thus  two  fiery  liquids  combine  to  produce  a  solid 
having  no  resemblance  to  either  of  them.  By  heat 
this  salt  may  be  converted  into  HgO  and  N2O.  (See 
p.  32.)  All  the  salts  of  ammonium  are  decom- 
posed by  heat. 

THE  RARE  METALS  OF  THE  ALKALIES. 

Lithium  (Li),  Rubidium  (Rb),  and  Caesium  (Cs)  are 
much  rarer  than  K  and  Na.  Li  is  the  lightest  of  all 
metals  (specific  gravity  0.59)  and  it  has  the  lowest' 
atomic  weight  (7).  The  metal  and  its  salts  resemble 
Na  and  its  salts,  while  Rb  and  Cs  are  more  like  K, 
Cs  was  the  first  metal  discovered  by  spectrum  an- 
alysis.   (See  page  147.) 


138 


INORGANIC     CHEMISTRY. 


METALS  OF  THE  ALKALINE  EARTHS. 

Ca,  Ba,  and  Sr. 


CALCIUM. 


Pio.  58. 


Symbol,  Ca Atomic  Weigljt,  40 Specific  Gravity,  1.57, 

Ca  exists  abundantly  in  limestone,  gypsum,  and  in 
the  bones  of  the  body.*  It  commonly  occurs,  in 
nature,  as  sulphate  or  carbonate ;  and,  in  commerce, 
as  oxide. 

Compounds. —  Calcium    Oxide     (CaO),    Caustic    or 

Quicklime^  is  obtained  by 
heating  limestone  (CaCOa) 
in  large  kilns.  The  COg  is 
driven  off  by  the  heat,  and 
the  CaO  is  left  as  a  white 
solid. 

Fig.  58  shows  a  form  of 
lime-kiln  in  which  the  proc- 
ess is  continuous.  At  a, 
ft,  c,  are  the  doors  for  the 
fuel,  ash-pit,  etc.  The  kiln 
is  fed  at  the  top  with  lime- 
stone from  time  to  time, 
while  the  lime,  settling  at 
the  bottom,  is  taken  out  at  /  as  fast  as  it  is  formed. 

*  "  There  are  5  lbs.  of  phosphate  of  lime,  one  of  carbonate  of  lime,  and 
3  oz.  of  fluoride  of  calcium  in  the  body  of  an  adult  weighing  154  lbs."— 
Nichols. 


r^So;<^:^ 


Limt-kilii. 


CALCIUM.  139 

Properties. — CaO  has  such  an  affinity  for  H2O,  that 
fifty-six  pounds  of  lime  will  absorb  eighteen  pounds 
of  H2O,  forming  Ca(0H)2,  calcium  hydroxide  or 
"slaked  lime,"  expanding  to  several  times  its  original 
size,  with  the  evolution  of  much  heat.  CaO  absorbs 
H2O  from  the  air,  and  then  CO2,  and  gradually  crum- 
bles to  a  coarse  powder,  becoming  "air-slaked  lime." 
Hydraulic  lime  is  made  from  limestone  containing 
more  than  10  per  cent,  of  silica,  and  will  harden 
under  water. 

Calcium  Hydroxide,  Ca(0H)2,  is  slightly  soluble  in 
water,  and  its  clear  solution  is  called  "  lime-water." 
A  film  of  calcium  carbonate  will  soon  form  on  the 
surface  of  lime-water  when  exposed  to  the  air.  Lime- 
water  has  an  alkaline  reaction,  /.  e.,  will  turn  red 
litmus  blue,  and  acts  as  a  mild  alkali. 

Uses. —  Whiteivash  is  a  "milk  of  lime,"  i.e.,  lime 
diffused  through  water.  Co7ic7^ete  is  a  cement  of 
coarse  gravel  and  hydraulic  lime.  It  is  of  great 
durability.  Hard  finish- is  a  kind  of  plaster  in  which 
gypsum  is  used  to  make  the  wall  smooth  and  hard. 
Calcimine  is  a  variety  of  whitewash  made  of  whiting 
or  plaster  of  Paris.  Mortar  is  a  mixture  of  lime  and 
sand  wet  with  H2O.  It  hardens  by  absorbing  CO2 
from  the  air  to  form  a  carbonate,  and  partly,  perhaps, 
by  uniting  with  the  Si02  of  the  sand  to  form  a 
silicate.* 

♦  "If  common  mortar  be  protected  from  the  air,  it  will  remain  without 
hardening  for  many  years.  It  is  staled  that  lime  still  in  the  condition  of 
a  hydrate  has  been  found  in  the  Pyramids  of  Egypt.  When  the  ruins  of 
the  old  castle  of  Landsberg  were  removed,  a  lime-pit,  that  must  have  been 
in  existence  three  hundred  years,  was  found  in  one  of  the  vaults.    The  sur- 


l-iO  INORGANIC     CHEMISTRY. 

Lime  is  valuable  as  a  fertilizer.  It  acts  by  rapidly 
decomposing  all  vegetable  matter,  and  thus  forming 
NH3  for  the  use  of  plants.*  It  also  sets  free  the 
alkalies  that  are  combined  in  the  soil,  and  furnishes 
them  to  the  plants,  becoming  itself  a  carbonate. 
Lime  is  also  used  extensively  in  the  preparation  of 
bleaching  powder,  in  refining  sugar,  in  making  can- 
dles, in  tanning,  and  in  the  manufacture  of  coal-gas. 

Calcium  Carbonate,  CaCOs,  includes  limestone, 
chalk,  marble,  and  marl,  and  forms  the  principal 
part  of  corals,  shells,  etc.  HjO  charged  with  CO2  dis- 
solves CaCOg,  which,  when  the  gas  escapes  on  ex- 
posure to  the  air,  is  deposited.  In  limestone  regions, 
the  water  trickling  down  into  caverns  has  formed 
"stalactites,"  which  depend  from  the  ceiling,  and 
"stalagmites,"'  that  rise  from  the  floor.  These  fre- 
quently assume  curious  and  grotesque  forms,  as  in 
many  limestone  caves.  Around  many  springs,  the 
water,  charged  with  CaCOg  in  solution,  flows  over 
moss  or  some  vegetable  substance,  upon  Avhich  the 
stone  is  deposited.  The  spongy  rock  thus  formed  is 
called  calcareous  tufa,  or  "petrified  moss."'  (See 
"Geology,"  page  49.)  Marble  is  crystalline  limestone. 
Chalk  or  marl  is  a  porous  kind  of  limestone,  formed 


face  was  carbonated  to  the  depth  of  a  few  inches,  but  the  lime  below  this 
was  fresh  as  if  just  slaked,  and  was  used  in  laying  the  foundations  of  the 
new  building." — Americau  Vydopedia. 

*  If  applied  to  a  compost  heap,  it  will  set  free  NH,,  thus  robbing  it  of 
its  most  valuable  constituent.  This  can  be  saved  by  sprinkling  the  pile 
with  dilute  HjSO.,  or  pla.ster,  or  by  mixing  it  with  dr>'  muck,  which  will 
absorb  the  gas.  If  there  is  any  copperas  (produced  by  the  oxidation  of  iron 
pyrites)  in  the  soil,  the  lime  will  decompose  it.  forming  gypsum  and  iron- 
rust,  thus  changing  a  noxious  ingredient  into  an  element  of  fertility. 


141 


A  caii   ivith  stalactites  and  stalagmites. 

from    beds    of    shells,    but    not    compressed    as    in 
common  limestone.     Whiting  is  ground  chalk. 

Calcium  Sulphate,  (CaS04,2H20),  Gijiysum,  Plaste7% 
etc.* — This  occurs  as  beautiful  fibrous  crystals  in 
satin  spar,  as  transparant  plates  in  selenite,  and  as  a 
snowy-white  solid  in  alabaster.  It  is  soft,  and  can  be 
cut  into  rings,  vases,  etc.  When  heated  it  loses  its 
water  of  crystallization,  and  is  ground  into  powder, 
called  "Plaster  of  Paris,"  from  its  abundance  near 
that  city.     Made  into  a  paste  with  H2O,  it  first  swells 


*  Comparing  the  formula  H^SO,  and  CaSO,,  we  see  that  one  atom  of 
Ca  can  replace  two  atoms  of  H ;  it  is  therefore  one  of  the  class  of  atoms 
called  bivalent. 


142  INORGANIC     CHEMISTRY. 

up,  and  then  immediately  hardens  into  a  sohd  mass. 
This  property  fits  it  for  use  in  copying  medals  and 
statues,  forming  molds,  fastening  metal  tops  on 
glass  lamps,  etc.  Plaster  (unburned  or  burned 
gj^sum)  is  used  as  a  fertilizer.*  Its  action  is  prob- 
ably somewhat  like  that  of  lime,  and  in  addition  it 
gathers  up  ammonia  and  holds  it  for  the  plant. 

Calcium  Sulphite,  CaSOg,  should  be  distinguished 
from  the  sulphate.  It  is  much  used  in  preserving 
cider,  being  sold  as  "sulphite  of  lime." 

Calcium  Phosphate,  ''Phosphate  of  Lime,''  is  fre- 
quently termed  hone  i)hosphate^  as  it  is  a  constituent 
of  bones.  (See  p.  113.)  It  is  found  as  a  mineral  in 
Florida,  South  Carolina, f  and  Canada.  It  is  the  valu- 
able part  of  certain  guanos.  Fertilizers  are  prepared 
by  treating  ground  bones  with  H2SO4,  forming  the 
so-called  superphosphate  of  lime,t  a  mixture  of  gyp- 
sum and   hydrogen  calcium   phosphate.    The  latter 

*  It  is  said  that  Franklin  brought  CaSO,  into  use  by  sowing  it  over  a 
field  of  grain  on  the  hill-side,  so  as  to  form,  in  gigantic  letters,  the  sentence, 
"Effects  of  gj-psuni."  The  rapid  growth  produced  soon  brought  out  the 
words  in  bold  relief,  and  decided  the  destiny  of  gj-psum  among  farmers. 

t  "  Along  the  coast  of  South  Carolina  are  millions  of  tons  of  rocks  hold- 
ing this  important  element  of  plant-food.  The  phosphatic  beds  extend  over 
an  area  of  several  hundred  square  miles,  and  in  some  cases  they  are  twelve 
feet  thick.  It  is  estimated  that  from  500  to  1000  tons  underlie  each  acre." 
— Fireside  Science. 

t  CajSPO,  (tricalcium  phosphate)  +2H,SO,  =  H.Ca2PO,  (acid  phosphate 
or  superphosphate)  +2CaSO,  (calcium  sulphate).  As  the  gjrpsum  is  only 
slightly  soluble  in  water,  the  sui)erphosphate  may  be  removed  from  the 
mass  by  filtering,  and  used  as  a  fertilizer,  or  to  form  phosphorus.  In  that 
case  it  is  converted  into  calcium  metaphosphate,  CaSPOj,  liy  evaporating 
and  heating  the  residue  to  redness,  and  then  mixed  with  C  and  heated 
again  in  earthenware  retorts.    The  following  reaction  takes  place  : 

3Ca2P03  +  10C^4P  +  Ca32PO,  +  lOCO, 
being  partly  changed  back  into  the  original  form,  CajSPO,. 


STRONTIUM     AND     BARIUM.  143 

furnishes  phosphorus  to  the  growing  plant  to  store 
in  its  seeds. — Example  :  corn,  wlieat. 

Calcium  Hypochlorite  (CaClaOg)  is  an  ingredient 
of  chloride  of  lime  or  "bleaching  powder."  This  is 
prepared  by  passing  a  current  of  CI  over  pans  of 
freshly  slaked  lime.  It  is  much  used  in  bleaching 
and  as  a  disinfectant. 

Calcium  Chloride,  the  other  compound  of  bleach- 
ing powder,  was  made  in  preparing  CO2  (see  p.  63). 
It  is  used  by  chemists  for  drying  gases.  It  absorbs 
H2O  so  greedily  that  in  the  open  air  it  will  soon 
dissolve. 


STRONTIUM     AND     BARIUM. 

These  metals  are  very  like  Ca.  The  salts  of  Ba 
give  a  green  tint  to  a  flame  and  those  of  Sr  a  beauti- 
ful crimson ;  and  are  hence  much  used  in  pyrotechny. 
Barium  sulphate,  commonly  called  barytes,  is  found 
as  a  white  mineral,  noted  for  its  weight,  whence  it 
is  often  termed  heavy  spar.  Indeed,  the  term  barium 
is  derived  from  a  Greek  word  meaning  heavy.  This 
mineral  is  largely  used  for  adulterating  white-lead. 
BaClg  is  a  test  for  H2SO4.     (See  p.  106.) 

Strontium  occurs  as  celestite,  SrS04,  and  as  stron- 
tianite,  SrCOg.  Its  most  important  compounds  are  : 
the  hydroxide,  Sr(0H)2,  which  is  used  in  sugar- 
making  to  extract  the  sugar  from  molasses ;  and 
the  nitrate,  Sr2N03,  which  is  used  as  a  constituent 
of  "red  fire."  The  metals  themselves  are  prepared 
with  difficulty,  and  are  of  no  practical  importance. 


144  INORGANIC     CHEMISTRY. 

MAGNESIUM.* 

Symbol,  f^g  .  .  .  .  Alonjic  Weight,  24,3  ....  Specific  Gravity,  1.7. 

Source. — Mg  is  found  in  augite,  hornblende,  nicor- 
schaum,  soap-stone,  talc,  .scrpentiiu",  dolomite,  and 
other  rocks.  Its  salts  give  the  bitter  taste  to  sea- 
water.  When  pure,  it  has  a  silvery  luster  and 
appearance.  It  is  very  light  and  fl(>xible.  A  thin 
ribbon  of  the  metal  will  take  lir(^  from  an  ignit(>d 
match,  and  burns  with  a  white  cloud  of  MgO,  pro- 
ducing such  a  brilliant  light  that  an  ordinary  llanu^ 
casts  dense  .shadow.s.  This  light  possesses  such 
actinic  or  chemical  properties,  that  it  is  used  for 
taking  photographs  at  night,  views  of  coal  mines, 
interiors  of  dark  (churches,  etc.  It  has  every  ray  of 
th(^  spectrum,  and  so  doi's  not,  like  gas-light,  change 
some  of  the  colors  of  an  object  upon  which  it  falls. 
Magnesium  lanterns  are  occasionally  used  for  purposes 
of  illumination.  By  means  of  clockwork,  the  meta,l, 
in  th(^  form  of  a  narrow  ribbon,  is  fed  in  front  of  a 
concave  mirror,  at  the  focus  of  which  it  burns.  Mg 
is  prepared  from  its  chloride,  MgClj,  by  electrolysis, 
or  by  reduction  by  means  of  Na.  It  is  hoped  that 
the  process  of  manufacture  may  be  cheapened,  so 
that  Mg  may  l)e  brought  within  the  scope  of  the 
arts. 

•  With  Mr  .arc  rlasscd  Zn,  Ci\,  .and  Ol.  Mr  Is  tr«vvto<l  horo  for  con- 
vonicnoo,  while  Zn  ia  doacribcd  iinionu  the  useful  nietiUs.  t'll  is  used  in 
m.-ikiiiR  some  iilUiys  and  it^  sjilts  are  enipU\ved  to  stinie  extent  in  phot-tiR- 
raphy  and  njodicine.  Ol  occurs  in  beryl  and  emerald.  It  ia  of  no  practical 
importance. 


ALUMINIUM.  145 

Compounds. — ^^  Magnesia  alba,''  the  common  mag- 
nesia of  the  druggist,*  is  a  basic  magnesium  car- 
bonate. Magnesiui It  sulphate  (MgS04,7H20)  is  known 
as  Epsom  salt,  from  a  celebrated  spring  in  England 
in  which  it  abounds. 


ALUMINIUM. t 
Symbol,  Al Atomic  Weight,  27 Specific  Gravity,  2.G. 

Source. — Al  is  named  from  alum,  in  which  it 
occurs.  It  Ls  also  called  the  "clay  metal."'  It  is  the 
metallic  base  of  clay,  mica,  slate,  and  feldspar  rocks. 
Xext  to  0  and  Si,  it  is  probably  the  most  abundant 
element  of  the  earth's  crust.  It  is  a  bright,  silver- 
white  metal ;  does  not  oxidize  in  the  air,  nor  tarnish 
by  HgS.  It  gives  a  clear  musical  ring;  is  only  one 
fourth  as  heavy  as  Ag ;  is  ductile,  malleable,  and 
tenacious.  It  readily  dissolves  in  HCl,  and  in  solu- 
tions of  the  alkalies,  but  with  difficulty  in  HNO3  and 
H2SO4.  On  account  of  its  abundance  (every  clay- 
bank  Ls  a  mine  of  it)  and  useful  properties,  it  must 
ultimately  come  into  common  use  in  the  arts  and 
domestic  life. 

Compounds. —  Aluminium  Oxide  (AI2O3). — Alumina 
crystallized  in  nature,   forms  valuable   gems.    They 

*  The  ma^rnesia  of  commerce  is  made  by  mixing  hot  solutions  of 
magnesium  sulphate  and  sodium  carbonate.  It  contains  a  varying  pro- 
ixjrtion  of  magnesium  hydrate.  Dolomite,  a  roc-k  composed  of  magnesium 
carbonate  and  calcium  carbonate,  makes  a  hydraulic  cement  that  "sets" 
under  water.— ("Greolog>%"  p.  .51.) 

+  Quite  a  number  of  rare  metals  fOa,  In,  Sc,  etc.)  are  classed  with  Al,  but 
none  of  them  are  of  sufficient  interest  to  be  treated  in  an  elementary  work. 


146 


INORGANIC    CHEMISTRY. 


are  variously  colored  by  impurities ; — blue,  in  the 
sapphire ;  green,  in  the  Oriental  emerald ;  yellow,  in 
the  Oriental  topaz ;  red,  in  the  ruby.  Massive,  impure 
alumina  is  called  emery,  and  used  for  polishing. 

Aluminium  Silicate,  Silicate  of  Alumina,  Com- 
mon Clay. — When  rocks '  decay  by  the  resist- 
less and  constant  action  of  the  air,  rain,  and 
frost,  they  crumble  into  soil.  This  contains  clay, 
silica,  and  also  lime,  magnesia,  oxide  of  iron,  etc. 
The  clay  gives  firmness  to  the  soil  and  retains 
moisture,  but  is  cold  and  tardy  in  producing  vege- 
table growth.  "When  free  from  Fe,  it  is  used  for 
making  tobacco-pipes.  When  colored  by  ferric  oxide, 
it  is  known  as  ocher,  and  is  employed  in  painting. 
Common  stone  and  red  earthen-ware  are  made  from 
coarse  varieties  of  clay;  porcelain  and  china-ware 
require  the  purest  material.  Fire-bricks  and  crucibles 
are  made  from  a  clay  which 
contains  much  Si02.  Fullers' 
earth  is  a  very  porous  kind,  and 
by  imbibition  absorbs  grease  and 
oil  from  cloth. 

Glazing. — When  an}^  article  of 
earthen-ware  has  been  molded 
from  clay,  it  is  baked.  As  the 
ware  is  porous,  and  will  not  hold 
H2O,  a  mixture  of  the  coarse  ma- 
terials from  which  glass  is  made 
is  tlicn  spread  over  the  vessel, 
and  heated  till  it  melts  and  forms 
a  glazing  upon  the  clay.   Ordinary  stone-ware  is  glazed 


Pig.  60. 


lUtkiiKj  Ih/rcilaiu. 


ALUMIXIITM.  147 

by  simply  throwing  dami3  NaCl  into  the  furnace.  This 
volatiHzes,  and  being  decomposed  by  the  hot  clay 
makes  a  sodium  silicate  over  the  surface,  while  fumes 
of  HCl  escape.  Pb  is  sometimes  used  to  give  a  yellow- 
ish glaze,  which  is  very  injurious,  as  it  will  dissolve 
in  vinegar,  and  form  sugar  of  lead,  a  deadly  poison. 
The  color  of  pottery-ware  and  brick  is  due  to  the 
oxide  of  iron  present  in  the  clay.  Some  varieties 
have  no  iron,  and  so  form  white  ware  and  brick. 

Alum  is  made  by  treating  clay  with  H2SO4,  form- 
ing an  aluminium  sulphate.  On  adding  potassium 
sulphate  a  double  salt  is  produced,  which  separates  in 
beautiful  octahedral  crystals  (Al23S04,K2S04  +  24H20). 
Instead  of  the  potassium  salt,  an  ammonium  salt* 
is  now  generally  added,  and  an  ammonium  alum 
made,  which  takes  the  place  of  the  former  in  the 
market. t  Alum  is  much  used  in  dyeing.  It  unites 
with  the  coloring  matter,  and  binds  it  to  the  fibers 
of  the  cloth.  It  is  therefore  called  a  mordant  (mor- 
deo,  I  bite). 


SPECTRUM     ANALYSIS. 

Some  of  the  metals  named  as  rare  have  been 
recently  discovered  by  what  is  termed  Spectrum 
Analysis.      "We    have    already    noticed    that    various 

*  Ammonium  sulphate,  from  the  ammoniacal  liquor  of  the  gas-works. 
(See  page  73.) 

t  There  are  a  large  number  of  other  alums  known,  in  -which  iron, 
chromium,  and  manganese  are  substituted  for  the  aluminium  in  common 
alum ;  all  these  alums  occur  in  regular  octahedra,  and  can  not  be  separated 
by  crystallization  when  present  in  solution  together. 


148  INORGANIC     CHEMISTRY. 

metals  impart  a  peculiar  color  to  flame ;  thus  Na 
gives  a  yellow  tinge ;  Cu,  a  green,  etc.  If  now  we 
look  at  these  colored  flames  through  a  prism,  we 
shali  find,  instead  of  the  "spectrum"  we  are  familiar 
with,  a  dark  space  strangely  ornamented  with  bright- 
tinted  lines.  Thus  the  spectrum  of  Na  has  one 
double,  yellow  line  ;  *  K,  a  violet  and  a  red  line  ;  Cs, 
two  beautiful  blue  lines.  Each  metal  makes  a  dis- 
tinctive spectrum,  even  when  the  flame  is  colored  by 
several  substances  at  once.  This  method  of  analysis 
is  so  delicate  that  t8o,ooo.ot>o  <->f  ^  grain  of  Na,  or 
6,000,000  of  L'>  can  be  detected  in  the  flame  of  an 
alcohol  lamp ;  f  while  a  substance  exposed  to  the  air 
for  a  moment  even  will  give  the  Na  lines  from  the 
dust  it  gathers.  Li  has  thus  been  found  to  exist  in 
tea,  tobacco,  milk,  and  blood,  although  in  such 
minute  quantities  as  to  have  eluded  detection  by 
former  methods  of  analysis. 


PRACTICAL     QUESTIONS. 

1.  In  the  experiment  with  Na,SO.  on  page  134,  an  accurate  the  - 
mometer  will  show  that  in  making  the  solution,  the  temperature  of  the 
liquid  will  fall,  and  in  its  solidification,  will  rise.    Explain. 

2.  If,  in  making  the  solution  of  NajSO,,  we  use  the  salt  which  has 
effloresced,  and  so  become  anhydrous,  the  temperature  will  rise  instead  of 
falling  as  before.    Explain. 

3.  Why  is  KNO3  used  instead  of  NaNOj  for  making  gunpowder? 

4.  Why  is  a  potassium  salt  preferable  to  a  sodium  one  in  glass-making? 

*  The  yellow,  sodium  line  consists  of  two  lines  lying  so  closely  together 
as  to  seem  as  one.  They  correspond  to  Fraunhofer's  lines  D,  as  given  in 
the  drawings  of  Kirchhoff  and  Bunsen. 

t  For  the  more  perfect  examination  of  the  spectra,  a  "  spectroscope  "  is 
used.  This  consists  of  a  tube  with  a  narrow  slit  at  one  end,  which  lets 
only  a  narrow  beam  of  light  fall  upon  the  prism  within,  and  at  the  other 
a  small  telescope,  through  which  one  can  look  in  upon  the  prism  and  ex- 
amine the  spectrum  of  any  flame.     (See  "Astronomy,"  p.  285.) 


PRACTICAL     QUESTIONS.  149 

5.  Wliat  is  the  glassy  slag  so  plentiful  about  a  furnace? 

6.  State  the  formulas  of  niter,  saleratus,  carbonate  and  bicarbonate  of 
soda,  plaster,  pearlash,  saltpeter,  plaster  of  Paris,  gypsum,  carbonate  and 
bicarbonate  of  potash,  sal-soda,  and  soda. 

7.  Explain  how  ammonium  carbonate  is  formed  in  the  process  of 
making  coal-gas. 

8.  Upon  what  fact  depends  the  formation  of  stalactites? 

9.  Why  is  HP  kept  in  gutta-percha  bottles? 

10.  Explain  the  use  of  borax  in  washing. 

11.  How  are  petrifactions  formed? 

12.  In  what  part  of  the  body,  and  in  what  forms,  is  phosphorus  found? 
13    Why  are  matches  poisonous?   What  is  the  antidote?    (See  "Physiol- 
ogy," page  209.) 

14.  Will  the  burning  phosphorus  ignite  the  wood  of  the  match? 

15.  What    principle   is    illustrated    in    the    ignition    of    a    match    by 
friction  ? 

16.  How  much  H2O  woTild  be  required  to  dissolve  a  pound  of  KNO3? 

17.  What  causes  the  bad  odor  after  the  discharge  of  a  gun? 

18.  Write  in  parallel  columns  (see  Question  41,  page  85),  the  properties 
of  common  and  of  red  phosphorus. 

19.  What  causes  the  diiference  between  fine  and  coarse  salt? 

20.  Why  do  zhe  figures  in  a  glass  paper-weight  look  larger  when  seen 
from  the  top  than  from  the  bottom  ? 

21.  AVhat  is  the  diff'erence  between  water-slaked  and  air-slaked  lime? 

22.  Why  do  oyster-shells  on  the  grate  of  a  coal-stove  prevent  the  forma- 
tion of  clinkers? 

23.  How  is  hme-water  made  from  oyster-shells? 

24.  Why  do  newly -plastered  walls  remain  damp  so  long? 

25.  Will  hme  lose  its  beneficial  effect  upon  a  soil  after  frequent  applica- 
tions ? 

26.  What   causes   plaster  of   Paris   to  harden  again   after  being  moist- 
ened? 

27.  What  is  the  difference  between  sulphate  and  sulphite  of  lime? 

28.  What  two  classes  of  rays  are  contained  in  the  magnesium  light? 

29.  What  rare  metals  would  become  useful  in  the  arts,  if  the  process  of 
manufacture  were  cheapened?  • 

30.  Why  is  lime  placed  in  the  bottom  of  a  leach-tub? 

31.  Is  saleratus  a  salt  of  K  or  of  Na? 

32.  Why  will  Na  burst  into  a  blaze  when  thrown  on  hot  water? 

33.  Why  are  certain  kinds  of  brick  white? 

34.  Illustrate  the  power  of  chemical  affinity. 

35.  Why  does  not  a  candle  lowered  into  a  jar  of  01  go  on  burning  in- 
definitely ? 


150 


INORGANIC     CHEMISTRY. 


THE   HEAVY    METiJLS, 


IRON. 

Synjbol,  Fe.  .  .  .  fi^iorqk  Weigljt,  56  ...  .  Specific  Gravity,  7.8. 

Iron  is  the  symbol  of  civilization.  Its  value  in 
the  arts  can  be  measured  only  by  the  progress  of 
the  present  age.  In  its  adaptations  and  employ- 
ments, it  has  kept  pace  with  scientific  discoveries 
and  improvements,  so  that  the  uses  of  iron  may 
readily  indicate  the  advancement  of  a  nation.  It  is 
worth  more  to  the  world  than  all  the  other  metals 
combined.  We  could  dispense  with  gold  and  silver — 
they  largely  minister  to  luxury  and  refinement — but 
iron  represents  solely  the  results  of  honest  labor.  Its 
use  is  universal,*  and  it  is  fitted  alike  for  massive 
iron  cables,  and  for  screws  so  tiny  that  they  can  be 
seen  only  by  the  microscope,  appearing  to  the  naked 
eye  like  grains  of  black  sand. 


*  "  Iron  vessels  cross  the  ocean, 
Iron  engines  give  them  motion, 
Iron  needles  northward  veering, 
Iron  tillers  vessels  steering. 
Iron  pipa  our  gas  delivers. 
Iron  bridges  span  oi;r  rivers. 
Iron  pons  are  used  for  writing. 
Iron  ink  our  thoughts  inditing. 
Iron  stoves  for  cooking  victuals. 
Iron  ovens,  pots,  and  kettles. 
Iron  horses  draw  our  loads, 
Iron  rails  compose  our  roads. 


Iron  anchors  hold  in  sands, 

Iron  bolts  and  rods  and  bands, 

Iron  houses,  iron  malls. 

Iron  cannon,  iron  balls, 

Iron  axes,  knives,  and  chains. 

Iron  augers,  saws,  and  planes. 

Iron  globules  in  our  blood, 

Iron  particles  in  food, 

Iron  lightning-rods  on  spires, 

Iron  telegraphic  wires. 

Iron  hammers,  nails,  and  screws, 

Iron  every  thing  we  use.'''' 


IRON.  151 

There  is  no  "California"  of  iron.  Each  nation 
has  its  own  supply.  No  other  material  is  so  en- 
hanced in  value  by  labor, 

1  lb.  good  iron  is  worth,  say $               .04 

1  "  bar  steel -17 

1  "  inch-screws 1.00 

1  "  steel  wire 3  to  7.00 

1  "  sewing-needles 14.00 

1  "  fish-hooks 20  to  50.00 

1  "  jewel-screws  for  watches 3,500.00 

1  "  hair-springs  for  American  watches 16,000.00* 

Source. — Fe  is  rarely  found  native,  i.  e.,  in  the 
metallic  condition.  Meteors,  however,  containing  as 
high  as  93  per  cent,  of  Fe  associated  with  Ni  and 
other  metals,  have  fallen  to  the  earth  from  space. 
Fe  in  combination  with  various  other  substances  is 
widely  diffused.  It  is  found  in  the  ashes  of  plants 
and  the  bloodf  of  animals.  Many  minerals  con- 
tain it  in  considerable  quantities.  The  ores  from 
which  it  is  extracted  are  generally  oxides  or  car- 
bonates. 

Preparation. — Smelting  of  Iron  Ores. — Fe  is  locked 
up  with  0  in  an  apparently  useless  stone.  C  is  the 
]^ey  that  is  ready  made  and  left  for  our  use  by  the 
Creator.  The  process  adopted  at  the  mines  is  very 
simple.  A  tall  blast-furnace  is  constructed  of  stone 
and  lined  with   fire-brick.    At   the    top  is  the  door, 

*  One  pound  (Troy)  of  fine  gold  is  worth  in  standard  coin  $248,062.  All 
the  above  statements  are  based  on  careful  and  actual  valuation. 

+  There  are  only  about  100  grains  of  Fe  in  the  blood  of  a  full-grown 
person— about  enough  to  make  a  ten-penny  nail— yet  it  gives  energy  and 
life  to  the  system.  The  metal  is  often  administered  as  a  tonic  in  the  form 
of  citrate  or  other  salt  of  iron,  and  is  a  valuable  medicine. 


152 


INORGANIC     CHEMISTRY. 


and  at  the  bottom  are  pipes  for  forcing  in  hot  air, 
sometimes  twelve  thousand  cubic  feet  per  minute, 
by  means  of  blowers  driven   by  steam-power.      The 


Fig.  61. 


A  Blast-Furnace. 


furnace,  after  a  fire  has  been  started,  is  filled  with 
limestone,  coal  (charcoal  or  coke),  and  iron  ore,  in 
alternate  layers.  The  C*  unites  with  the  0  of  the 
ore,  and   goes  off  as  CO  and  CO  2-    The  CaCOj   forms 


*  A  little  N  sometimes  unites  with  some  C  and  K,  forming  potassium 
cyanide,  or  with  Ti,  if  any  is  present,  making  beautiful  copper-colored 
crystals   of   titanium    cyano-nitride,   which    are    hard    enough   to  scratch 

glass. 


IRON.  153 

with  the  Si02  and  other  impurities  a  richly-colored 
glassy  slag.  The  iron,  as  it  is  reduced,  sinks  in  the 
molten  state  to  the  lowest  part  of  the  furnace  (the 
crucible),  covered  with  a  layer  of  slag.  The  slag 
runs  out  in  a  constant  stream  from  an  opening  at 
the  proper  height,  while  the  iron  is  drawn  off  from 
time  to  time  and  run  into  channels  formed  in  sand. 
The  large  main  one  is  called  the  soiv ;  the  smaller 
lateral  ones  are  termed  the  pigs — hence  the  name 
pig^ron. 

Varieties  of  Iron.  —  The  usual  forms  are  cast, 
wrought,  and  steel,  depending  upon  the  proportion 
of  C  which  they  contain.  Steel  contains  more  C 
than  wrought  iron,  and  less  than  cast.  The  highest 
proportion  of  C  in  cast  iron  is  about  6  per  cent., 
while  wrought  iron  contains  only  from  0.1 — 0.7  per 
cent. 

1.  Cast  Iron  is  the  form  which  comes  from  the 
furnace.  It  is  brittle,  can  not  be  welded,  and  is 
neither  malleable  nor  ductile.  It  is  well  adapted  for 
castings,  since  at  the  instant  of  solidification  it  ex- 
pands, so  as  to  copy  exactly  every  line  of  the  mold 
into  which  it  is  poured.  The  castings  may  be  made 
so  soft  as  to  be  easil}^  turned  and  filed,  or  so  hard, 
by  cooling  in  iron  molds,*  that  no  tool  will  affect 
them. 

2.  Wrought  or  Malleable  Iron  is  made  by  burn- 
ing the  C  from  cast  iron,  i^  a  current  of  highly-heated 
air,  in  what  is  called   a   reverberatory  furnace.    The 

*  These  molds  are  called  "  chills,"  and  the  iron  is  termed  chilled  iron. 
It  is  used  for  burglar-proof  safes. 


154 


INORGANIC     CHEMISTRY. 


Fio.  62. 


A  Reverberatory  Furnace. 


iron  is  stirred  constantly,  and  exposed  to  the  heated 
air  by  means  of  long  "  puddling-sticks,"  as  they  are 

termed.  It  is  taken  out  while 
white-hot,  and  beaten  under 
a  trip-hammer  to  force  out 
the  slag  ;  and  lastly,  pressed 
between  grooved  rollers  to 
bring  the  particles  of  Fe 
nearer  each  other  and  give 
it  a  fibrous  structure.*  It 
is  now  malleable  and  duc- 
tile,! much  softer  than  cast  iron,  and  can  be  welded. 
3.  Steel  contains  less  C  than  cast,  and  more  than 
wrought,  iron.  It  is  therefore  made  from  the  former 
by  burning  out  a  part  of  the  C,  and  from  the  latter 
by  heating  in  boxes  of  charcoal,  and  so  adding  C.J 
The  value  of  steel  depends  largely  upon  its  temper. 
This  is  determined  by  heating  the  article,  and  then 
allowing  it  to  cool.  The  higher  the  temperature  the 
softer  the  steel.  The  workman  decides  this  by 
watching  the  color  of  the  oxide  which  forms  on  the 


*  This  fibrous  structure  is  so  noticeable  that  if  a  bar  of  the  best  Fe  be 
noti^hed  with  a  cliisel  and  then  broken  by  a  steady  pressure,  the  fracture 
will  present  a  stringy  appearance,  like  that  of  a  green  stick.  By  constant 
jarring,  however,  Fe  tends  to  take  a  crystalline  structure,  becoming  rotten 
and  brittle,  so  that  cannon,  the  axles  of  cars,  etc.,  are  condemned  after  a 
certain  time,  although  no  flaw  may  appear. 

t  It  has  been  beaten  into  leaves  so  thin  that  they  have  been  used  for 
writing-paper— six  hundred  leaves  being  only  half  an  inch  in  thickness— 
and  has  been  drawn  into  wire  as  fine  as  a  hair. 

t  This  is  termed  ccvie-hardening.  Cheap  knives  made  of  soft  iron  are 
often  covered  with  a  superficial  coating  of  steel  in  this  way.  When  we 
use  such  knives,  we  soon  wear  through  this  crust,  and  find  metal  beneath 
which  will  take  no  edge. 


IRON.  155 

surface.*  Razors  require  a  straw  yellow ;  table- 
knives,  a  purple ;  springs  and  swords,  a  bright  blue  ; 
and  saws,  a  dark  blue  tint.f 

Bessemer's  Process  is  now  extensively  used  for 
making  steel.  Several  tons  of  the  best  pig-iron  are 
melted,  and  poured  into  a  large  crucible  hung  on 
pivots  so  as  to  be  easily  tilted.  Hot  air  driven  in 
from  beneath  bubbles  up  through  the  liquid  mass, 
producing  an  intense  combustion.  The  roar  of  the 
blast,  the  hot,  white  flakes  of  slag  ever  and  anon 
whirled  upward,  the  long  flame  streaming  out  at  the 
top,  variegated  by  tints  of  different  metals,  and  full  of 
sparks  of  scintillating  iron,  all  show  the  play  of  tre- 
mendous chemical  forces.  The  operation  lasts  about 
twenty  minutes,  when  the  Fe  is  purified  of  its  C  and 
Si.  Enough  spiegel-eisen  (looking-glass  iron),  from 
an  ore  rich  in  C  and  Mn,  is  added  to  convert  it  into 
steel,  when  it  is  poured  out  and  cast  into  ingots.| 

*  The  thin  pellicles  of  iron-rust  on  standing  H,0  produce  a  beautiful 
iridescent  appearance  in  the  same  way,  the  color  changing  with  the  thick- 
ness of  the  oxide.  Just  so  a  soap-bubble  exhibits  a  play  of  variegated 
colors  according  to  the  thickness  of  the  film  in  different  parts.  (See  "In- 
terference of  Light,"  in  "Physics.") 

t  These  colors  are  removed  in  the  subsequent  processes  of  grinding  and 
polishing,  but  they  may  be  seen  in  a  handful  of  old  watch-springs,  to  be 
obtained  of  any  jeweler. 

t  In  1760,  there  lived  at  AttercUflfe,  near  Sheffield,  a  watch-maker 
named  Huntsman.  He  became  dissatisfied  with  the  watch-springs  in  use, 
and  set  himself  to  the  task  of  making  them  homogeneous.  "  If,"  thought 
he,  "  I  can  melt  a  piece  of  steel  and  cast  it  into  an  ingot,  its  composition 
should  be  the  same  throughout."  He  succeeded.  His  steel  became  famous, 
and  Huntsman's  ingots  were  in  universal  demand.  He  did  not  call  them 
cast  steel.  That  was  his  secret.  The  process  was  wrapped  in  mystery  by 
every  means.  The  most  faithful  men  were  hired.  The  work  was  divided, 
large  wages  paid,  and  stringent  oaths  taken.  One  midwinter  night,  as  the 
tall  chimneys  of  the  AttercliflPe  steel-works  belched  forth  their  smoke,  a  be- 
lated traveler  knocked  at  the  gate.   It  was  Wtter  cold ;  the  snow  fell  fast ; 


156  INORGANIC     CHEMISTRY. 

Pure  Iron. — All  varieties  of  cast  iron,  wrought 
iron,  and  steel,  are  more  or  less  impure  forms  of  Fe. 
The  pure  metal  is  little  known,  but  can  be  prepared 
from  its  pure  salts  by  reduction  or  electrolysis. 

Compounds. — 1.  Black  or  Magnetic  Oxide  (Fe3  04) 
is  found  in  the  loadstone,  magnetic  iron  ore,  scales 
which  fly  off  in  forging  iron,  and  in  mines  in 
various  parts  of  the  United  States.  It  is  the  richest 
of  the  ores,  and  contains  as  high  as  72  per  cent,  of 
the  metal.  2.  Red  Oxide  of  Iron,  sesquioxide  (ferric 
oxide,  FegOg),  is  seen  in  red  iron  ore,  in  the  beau- 
tiful radiated  and  fibrous  specimens  of  hematite,* 
specular  t  iron,  red  ocher,  chalk,  bricks  and  pottery- 
ware.  The  sesquioxide,  combining  with  H2O,  forms — 
3.  Hydrated  Sesquioxide  of  Iron  (ferric  hydroxide, 
Fe(0H)3).  This  has  a  brown  or  yellow  color,  which 
changes  to  red  by  heat  when  the  water  is  expelled, 
as  in  the  burning  of  brick,  pottery-ware, J  etc.    These 


and  the  wind  howled  across  the  moor.  The  stranger,  apparently  a  common 
farm-laborer  seeking  shelter  from  the  storm,  awakened  no  suspicion.  The 
foreman,  scanning  him  closely,  at  last  granted  his  request,  and  let  him  in. 
Feigning  to  be  worn  out  with  cold  and  fatigue,  the  poor  fellow  sank  upon 
the  floor,  and  was  soon  seemingly  fast  asleep.  That,  however,  was  far  from 
his  intention.  Through  cautiously  opened  eyes,  he  caught  glimpses  of  the 
mysterious  process.  He  saw  workmen  cut  bars  of  steel  into  bits,  place  them 
in  crucibles,  which  were  then  thrust  into  the  furnaces.  The  fires  were 
urged  to  their  utmost  intensity  until  the  steel  melted.  The  workmen, 
clothed  in  rags,  wet  to  protect  them  from  the  tremendous  heat,  drew  forth 
the  glowing  crucibles,  and  poured  their  contents  into  molds.  Hunts- 
man's factory  had  nothing  more  to  disclose.  The  secret  of  cast  steel  was 
stolen. 

♦  IleevMtites,  blood-like,  from  the  red  color  of  it,s  powder. 

t  f!j>ea/lum,  a  mirror,  from  the  brilliant  luster  of  its  steel-gray  crystals 
and  mica-like  scales  in  micaceous  iron  ore. 

t  Clay,  containing  ferrous  oxide  (FeO),  becomes  red  by  its  conversion 
into  ferric  oxide. 


IRON,  157 

oxides  generally  give  the  brown,  yellow,  or  red  tints 
seen  in  sand,  gravel,  etc.  The  ferric  oxide  and  hy- 
drate are  remarkable  for  the  facility  with  which 
they  absorb  0  from  the  air,  and  impart  it  to  other 
bodies.  This  is  familiar  in  the  rusting  of  nails  in 
clapboards,  hinges  in  gate-posts,  hooks  in  ropes, 
etc.,  etc. 

Iron  Carbonate,  FeCOg,  is  found  as  spathic*  and 
clay  iron-stone,  and  often  contains  some  manganese,! 
which  fits  it  for  the  manufacture  of  certain  kinds  of 
steel,  whence  it  is  termed  steel  ore.  In  chalybeate 
springs,  the  free  CO 2  in  the  water  holds  the  FeCOa 
in  solution.  On  coming  to  the  air,  the  CO2  escapes, 
and  the  Fe,  absorbing  0,  is  deposited  as  hydrated 
ferric  oxide,  forming  the  ochry  deposit  so  common 
around  such  springs. 

Iron  Disulphide  (FeSa),  Iron  Pyrites,  FooVs  Gold — 
so  called,  because  it  is  often  mistaken  by  ignorant 
persons  for  Au.  It  occurs  in  cubical  crystals  and 
bright  shiny  scales.  It  can  be  easily  tested  by  roast- 
ing on   a   hot  shovel,  when  we  shall  catch  the  well- 

*  Spath,  spar,  as  some  specimens  consist  of  transparent,  shiny  crystals, 
having  the  same  form  as  calcareous  spar  (calcium  carbonate). 

t  Manganese  is  a  hard,  brittle  metal,  resembling  cast  iron  in  its  color 
and  texture.  It  takes  a  beautiful  polish.  Its  binoxide,  the  black  oxide  of 
manganese,  is  used  in  the  manufacture  of  O,  CI,  etc.  By  fusing  MnO^. 
KCIO3,  and  KOH,  a  dark,  green  mass  is  obtained  called  '^chameleon  mimral.'''' 
It  contains  potassium  manganate.  If  a  piece  of  this  be  placed  in  H,0,  the 
solution  will  undergo  a  beautiful  change  from  green,  through  various 
shades,  to  purple.  This  is  owing  to  the  gradual  formation  of  permanganic 
acid.  The  change  may  be  produced  instantaneously  by  a  drop  of  H,SO,. 
Potassium  permanganate  is  remarkable  for  the  facility  with  which  it 
parts  with  its  O,  and  thereby  loses  its  color.  It  is  used  extensively  as 
a  disinfectant,  and  as  a  test  of  the  presence  of  organic  matter.  (See 
page  48.) 


158 


INORGANIC     CHEMISTRY. 


known  odor  of  the  SO  2.  FeS2  is  used  as  a  source  of 
S,  and  is  roasted  to  furnish  SOg  in  the  manufacture 
of  H2SO4. 

Ferrous  Sulphate  (FeS04,7H20),  Green  Viti'iol, 
Copperas,  is  made  by  the  action  of  H2SO4  on  Fe,  and, 
at  Stafford,  Connecticut,  and  other  places,  from  FeS2, 
by  exposure  to  air  and  moisture.  It  is  used  in  dyeing, 
making  ink,  and  in  photography. 


Fig.  63. 


ZINC. 

Symbol,  Zn  .  .  .  .  Atonjic  Weight,  65,3  ....  Specific  Gravity,  6.9. 
Fusing  Point,  811°  F.  or  433°  C. 

Source. — Zn  is  found  as  ZnO,  or  red  oxide,  in  New 
Jersey,  and  as  ZnS,  or  zinc  blende,  in  many  places. 

Preparation. — ZnO*  is  smelted 
on  the  same  principle  as  iron  ore, 
by  heating  with  C.  The  reaction 
is  as  follows :  ZnO  +  C  =  Zn  +  CO. 
The  Zn  distils  from  the  crucible 
a  and  is  collected  in  the  receiver 
d  while  the  CO  escapes. 

Properties. — Zn  is  ordinarily 
brittle,  but  when  heated  to  200° 
or  300°  F.,  it  becomes  malleable, 
and  can  be  rolled  out  into  the 
sheet  Zn  in  common  use.  At  about 
400°  F.  it  is  so  brittle   that  it  can   l)e   powdered  in  a 


Reduction  of  Zinc  Ore. 


*  ZnS  is  roasted  to  convert  it  into  ZnO. 


ZINC.  159 

mortar.  It  burns  in  the  air  with  a  magnificent  bluish 
light,  forming  flakes  of  ZnO,  formerly  called  "Phi- 
losopher's Wool."  AVhen  exposed  to  the  air  Zn  soon 
oxidizes,  and  the  thin  film  of  oxide  formed  over  the 
surface  protects  it  from  further  change. 

Uses. — Its  economic  uses  are  familiar.  Sheet  iron 
coated  with  Zn  by  being  dipped  in  melted  Zn  forms 
what  is  termed  galvanized  iron.  Water-pipes  lined 
in  this  way  with  Zn  are  as  unsafe  as  lead  (see  p.  162) 
until  the  Zn  is  entirely  corroded.  The  oxide  and 
carbonate  of  zinc  are  rapidly  formed,  and  these 
poisonous  salts  remain  in  the  HgO.  There  is  the 
same  objection  to  metallic-lined  ice-pitchers.  Gal- 
vanic action  between  the  metals  promotes  corrosion. 
H2O  standing  in  reservoirs  lined  with  Zn  should  not 
be  used  for  drinking  purposes.  In  the  case  of  zinc- 
covered  roofs  the  rain-water  contains  zinc* 

Compounds.  —  Zinc  Oxide,  ZnO,  is  sold  as  zinc- 
white,  and  is  valued  as  a  paint,  since  it  does  not 
blacken  by  HgS  like  white-lead,  and  is  not  hurtful 
to  the  painter. 

Zinc  Chloride,  ZnCl2,  is  used  as  a  soldering  fluid, 
which  the  plumbers  prepare  by  "killing"  muriatic 
acid  with  Zn.  It  is  also  used  as  a  disinfectant  and 
for  a  number  of  technical  purposes. 

Zinc  Sulphate,  ZnS04,7H20,  White  Vitriol,  is  used 
as  a  "dryer"  in  oil  paints  and  varnishes.  It  is  de- 
composed, when  strongly  heated,  into  ZnO,  SO2,  and  0. 

*  When  they  were  first  introduced  in  Boston  the  washei'-wonien  com- 
plained that  the  rain-water  was  hard,  decomposed  the  soap,  and  made  their 
hands  crack. 


160  INORGANIC     CHEMISTRY. 


T    I    N. 

Symbol,  Sn  ....  Atomic  Weight,  119  ....  Specific  Gravity,  7.3. 
Fusing    Point,  446°  F.  or  230°  C. 

Source. — Sn,  though  one  of  the  metals  longest 
known  to  man,  is  found  in  but  few  localities.  It  is 
reduced  from  its  dioxide  by  the  action  of  C. 

Properties. — It  is  soft  and  not  very  ductile,  but  is 
quite  malleable,  so  that  tin-foil  is  not  more  than  -j-ffVrr 
of  an  inch  in  thickness.  When  quickly  bent,  a  bar  of 
Sn  emits  a  shrill  sound,  called  the  "tin  cry,"  caused 
by  the  crystals  moving  upon  each  other.  Sn  does  not 
oxidize  at  ordinary  terriperatures.  Its  tendency  to 
crystallize  is  remarkable.* 

Uses.  —  Common  sheet-tin  is  formed  by  dipping 
sheet-iron  in  melted  Sn,  which  produces  an  artificial 
coating  of  the  latter  metal.  If  we  leave  HjO  in  a  tin 
dish,  the  yellow  spots  soon  betray  the  presence  of  Fe. 
Pins  are  made  of  brass  wire,  upon  which  a  bright 
white  coating  of  tin  is  deposited.!  Tin  is  a  constit- 
uent of  a  number  of  important  alloys  (see  p.  177). 
It  forms  two  classes  of  salts :  the  stannous,  in  which 
it  is  bivalent,  and  the  stannic,  in  which  it  is  quad- 
rivalent.   E.  g.,  SnCl2  and  SnCl4. 

*  Example:  Heat  a  piece  of  tin  till  the  coating  begins  to  melt;  then 
cool  quickly  in  HjO  and  clean  in  dilute  acjua  regla.  The  surface  will  be 
found  covered  with  beautiful  crystals  of  the  metal. 

t  The  pins  are  stuck  in  papers,  as  we  see  them,  by  machinery  which 
picks  them  up  out  of  a  miscellaneous  pile  and  inserts  them  in  regular  rows 
in  the  paper,  ready  for  the  market.  The  fli-st  part  of  the  process  is  per- 
formed by  a  sort  of  coarse  comb,  which  is  thrust  into  the  heap,  and  gathers 
up  a  pin  in  each  of  the  spaces  between  the  teeth. 


COPPER.  161 


COPPER. 

Synjbol,  Cu.  .  .  .  Atonjic  Weight,  63.6  ....  Specific  Gravity,  8.9. 
Fusing  Point,  about  2012°  F.  or  1100°  C. 

Source. — Cu  is  found  native  near  Lake  Superior, 
frequently  in  masses  of  great  size.  In  these  mines 
stone  hammers  have  been  discovered,  the  tools  of  a 
people  older  than  the  Indians,  who  probably  occupied 
this  continent,  and  worked  the  mines.  In  the  western 
mounds,  also,  copper  instruments  are  found.  The 
sulphide,  copper  pyrites,  is  a  well-known  ore.  Mal- 
achite (CuC03,Cu[0H]2),  the  green  carbonate,  admits 
of  a  high  polish,  and  is  made  into  ornaments  of  ex- 
quisite beauty. 

Properties. — Cu  is  ductile,  malleable,  and  an  ex- 
cellent conductor  of  heat  and  electricity.*  Its  vapor 
gives  a  characteristic  and  beautiful  green  color  to 
flame.  HNO3  is  the  solvent  of  Cu.  Its  test  is  NH4.OH, 
forming  in  a  solution  a  blue  precipitate,  which  dis- 
solves in  an  excess  of  the  re-agent  with  an  intense 
dark  blue  color. 

Compounds. — Copper  Acetate,  Verdigris,]  is  pro- 
duced when  we  soak  pickles  in  brass  or  copper 
kettles ;  the  green  color  which  results  is  caused  by 
this  salt — a  deadly  poison.  Preserved  fruits,  etc., 
should  never  stand  in  such  vessels,  as  the  vegetable 
acids  dissolve  Cu  readily. 

♦  Commercial  Cu  is  never  quite  pure.  Its  properties  are  affected  very 
markedly  by  the  presence  of  even  minute  amoiints  of  foreign  substances. 

+  The  term  verdigris  is  sometimes  incorrectly  applied  to  the  green  coat- 
ing of  carbonate,  which  gathers  upon  brass  or  copper  in  a  damp  atmosphere. 


162  INORGANIC     CHEMISTRY. 

Copper  Oxide,  CuO,  is  the  black  coating  which 
is  formed  on  copper  or  brass  kettles.  Such  utensils 
should  therefore  be  used  only  when  perfectly  bright, 
and  never  with  fruits,  sweetmeats,  jellies,  pickles, 
etc. 

Copper  Sulphate  (CuS04,5H20),  Blue  Vitriol,  is 
much  used  in  dyeing,  calico  printing,  and  in  voltaic 
batteries. 


LEAD. 

Symbol,  Pb. ..  .Atomic  Weight,  207 Specific  Gravity,  11.36. 

Fusing  Point,  835°  F.  or  335°  C. 

Source. — The  most  common  ore  of  Pb  is  galena, 
PbS,  which  is  reduced  by  processes  which  differ  ac- 
cording to  the  purity  of  the  ore. 

Properties. — Pb  is  malleable ;  but  contracts  as  it 
solidifies,  so  it  can  not  be  used  for  castings.  Lead 
itself  is  not  poisonous,  and  "  bullets  have  been 
swallowed,  and  then  thrown  off  without  any  harm 
except  the  fright."  The  soluble  salts  of  Pb  are,  how- 
ever, all  very  poisonous.  The  effects  seem  to  ac- 
cumulate in  the  system,  and  finally  to  manifest 
themselves  in  disease.  Persons  who  work  in  lead 
compounds,  as  painters,  after  a  time  suffer  with 
colics,  paralysis,  etc.,  while  plumbers,  who  handle 
only  metallic  Pb,  do  not  suffer. 

Uses. — Pb  is  much  used  for  water-pipes,  and  is 
the  most  convenient  of  any  metal  for  that  purpose. 
Pure  HgO  passing  through  the  pipe  will  not  corrode 
the   Pb,  but   the  0  of   the    air   it   contains   forms    an 


LEAD.  163 

oxide  of  lead  which  dissolves  in  the  HgO,  leaving  a 
fresh  surface  for  oxidation.  If  there  are  any  sul- 
phates or  carbonates  in  the  H2O,  they  will  form  a 
coating  over  the  Pb,  and  protect  it  from  further 
corrosion ;  and  as  carbonate  of  lime  is  common  in 
hard  water,  that  is  generally  safe.  If,  when  we 
examine  a  lead  pipe  that  is  in  constant  use,  we  find 
it  covered  with  a  white  film,  it  is  a  good  sign ;  but 
if  it  is  bright,  there  is  cause  for  alarm.  Still,  how- 
ever much  may  be  said  about  the  danger,  people  will 
use  lead  pipes,  and  the  following  precautions  should 
be  observed :  Before  using  the  tvater  in  the  morning, 
always  let  it  run  long  enough  to  remove  all  which  has 
remained  in  the  water-pipes  during  the  night;  and 
when  the  H2O  is  let  on  again  after  it  has  been  shut 
off  for  awhile,  leave  the  faucet  open  until  the  pipe 
is  thoroughly  'washed. 

The  Test  of  Pb  is  H2S,  forming  lead  sulphide, 
PbS.  The  following  is  an  interesting  illustration : 
Thicken  a  solution  of  lead  acetate  with  a  little  gum- 
arabic,  so  as  not  to  flow  too  readily  from  the  pen, 
and  then  make  any  sketch  which  your  fancy  may 
suggest.  This,  when  dry,  will  be  invisible.  When 
it  is  to  be  used,  dampen  the  paper  slightly  on  the 
wrong  side,  and  then  direct  against  it  a  jet  of  H2S. 
The  picture  will  at  once  blacken  into  distinctness.* 

Compounds.  —  Lead  Oxide,  PbO,  the  well-known 
litharge,   is   formed   by  heating    Pb   in   a   current   of 

*  A  delicate  test  for  the  presence  of  lead  in  water  is  this :  Add  a  few 
drops  of  acetic  acid  and  then  a  small  pinch  of  powdered  bichromate  of 
IX)taasium  (K,CraO,).    If  Pb  is  present,  a  yeUow  turbidity  will  appear. 


164 


INORGANIC     CHEMISTRY 


Fig.  64. 


air.*  Lead  Dioxide,  PbOg,  is  formed  by  oxidizing 
PbO.  A  mixture  of  the  two,  called  redr-lead,  is  used 
for  coloring  red  sealing-wax,  and  as  a  paint. 

Lead  Carbonate  (PbCOa),  White- Lead,  consists 
of  basic  lead  carbonates,  and  is  made  as  follows : 
Thousands  of  earthen  pots  fitted  with 
covers  and  containing  weak  vinegar 
(acetic  acid)  and  a  small  roll  of  Pb,  are 
arranged  in  piles,  and  then  covered 
with  tan-bark.  The  acetic  acid  com- 
bines with  the  Pb,  but  the  CO 2  formed 
by  the  decomposing  tan-bark  creeps  in 
under  the  cover,  driving  off  the  acetic 
acid,  and  forming  lead  carbonate.  The 
acetic  acid,  thus  dispossessed,  attacks 
another  portion  of  the  Pb,  but  is  robbed 
again  ;  and  so  the  process  goes  on,  till  the  Pb  is  ex- 
hausted. White-lead  is  often  adulterated 
with  heavy  spar,  gypsum,  etc. 

Lead  Acetate,  Sugar  of  Lead,  has  a 
sweet,  pleasant  taste,  but  is  a  virulent 
poison.  Its  antidote  is  Epsom  salt,  which 
forms  an  insoluble  lead  sulphate.  H2O  dis- 
solves sugar  of  lead  readily.  If  a  piece  of 
Zn,  cut  in  small  strips,  be  suspended  in  a 
bottle  filled  with  a  solution  of  lead  acetate, 
the  Pb  will  be  deposited  upon  it  by  voltaic  action  in 
beautiful  metallic  spangles,  forming  the  "  lead-tree." 


A. — An   earthen 

pot. 
Li.—  A    coil    of 

lead. 
V.  —  A    solution 

of  vinegar. 


FiQ.  65. 


*  Exatnple :  Heat  a  bit  of  lead  upon  charcoal  in  the  oxidizing  flamo  of 
the  blow-pipe.  A  film  of  the  suboxide  forms  first,  then  a  yellow  crust 
ot  the  oxide. 


GOLD.  165 

I 

THE    NOBLE    METALS. 

^u,    ^g,    Pt,    Hg,    Pd,    Ir,    Os,    Ru,    aijd    Ro. 


GOLD. 

Symbol,  Au ....  Atomic   Weight,   197.2  ....  Specific   Gravity,  19.84. 
Fusing  Point,  about  2012°  F.  or  1100°  C. 

Sources. — Au  is  sometimes  found  in  masses  called 
nuggets,  but  generally  in  scattered  grains,  or  scales. 
As  the  rocks  in  which  it  occurs  disintegrate  by  the 
action  of  the  elements  and  form  soil,  the  Au  is 
gradually  washed  into  the  valleys  below,  and  thence 
into  the  streams  and  rivers  where,  owing  to  its 
specific  gravity,  it  settles  and  collects  in  the  mud 
and  gravel  of  their  beds.* 

Preparation. — As  the  metal  is  thus  found  native, 
the  process  is  purely  mechanical,  and  consists  simply 
in  washing  out  the  dirt  and  gravel  in  wash-pans, 
rockers,  sluices,t  etc.,  at  the  bottom  of  which  the  Au 
accumulates.  In  the  quartz-mills,  the  rock  is  thrown 
into   troughs   of  water  where   by  heavy   stamps  the 

*  In  California,  Au  is  found  in  the  detritus  (small  particles  of  rock 
■worn  off  by  attrition)  of  granite  and  quartz.  It  occurs  in  the  gravel  of 
hills  from  the  surface  to  the  "  bed-rock,"  sometimes  a  depth  of  300  to  500 
feet ;  in  the  alluvial  soil  of  the  plains,  and  even  in  vegetable  loam  among 
the  roots  of  grass. 

+  Sluices  are  generally  used  in  California.  These  are  gently  inclined 
troughs,  sometimes  extending  for  miles.  Across  the  bottom  are  fastened 
low  wooden  bars,  called  I'iffles,  above  which  quicksilver  is  placed.  The  dirt 
is  shoveled  into  these  sluices,  or  the  auriferous  hills  are  cut  down,  dis- 
solved, and  washed  through  them  by  powerful  streams  of  water,  which  are 
constantly  running.  The  H,0  floats  off  the  debris,  while  the  Hg  catches 
the  ?old. 


166  INORGANIC     CHEMISTRY. 

ore  is  crushed  to  powder.  As  the  thin  liquid  mud 
thus  formed  splashes  up  on  either  side,  it  runs  over 
broad,  metallic  tables  covered  with  Hg;  or  is  washed 
through  a  fine  wire-screen,  and  carried  to  the 
"  amalgamating-pans "  by  a  little  stream  of  water. 
The  Hg  unites  with  the  particles  of  Au  and  forms 
with  them  an  amalgam  (a  compound  of  mercury 
and  a  metal).  Hg  is  easily  separated  from  Au  by  dis- 
tillation,* and  collected  to  be  used  again. 

Quartation. — Au  is  commonly  found  alloyed  with 
Ag.  The  Ag  is  then  dissolved  out  by  HNO3.  There 
must  be  at  least  three  parts  of  Ag  to  one  of  Au,  else 
the  gold  will  protect  the  silver  from  the  action  of 
the  acid.  Au  is  also  found  alloyed  with  copper,  iron, 
and  other  metals,  f 

Properties. — Pure  Au  is  nearly  as  soft  as  Pb.  It  is 
extremely    malleable  X    and    ductile.      Its    solvent    is 

*  The  larger  part  of  the  Hg  is  separated  from  the  amalgam  by  pressure  in 
canvas  or  buckskin  bags,  the  liquid  Hg  escaping  through  the  pores,  while 
the  amalgam  is  left  quite  dry.    The  latter  is  then  "  retorted  "  for  distillation. 

+  "  In  works  for  the  refining  of  gold  and  silver,  the  processes  can  be 
conducted  economically  only  when  great  care  is  taken  to  avoid  the  loss  of 
any  particles  of  the  precious  metals.  Thus  all  the  old  crucibles  arc  ground 
and  treated  with  mercury,  and  after  as  much  gold  and  silver  as  possible 
have  been  extracted,  the  residues  are  sold  to  the  mveep-washers,  who  extract 
a  little  more  by  melting  with  lead.  The  very  dust  oflf  the  floors  is  collected 
and  treated  in  a  similar  way."— Bloxam. 

t  For  a  description  of  the  process  of  making  gold-leaf,  see  "  Physics,"  page 
20.  "  When  one  of  these  leaves  is  held  up  to  the  light,  it  exhibits  a  beauti- 
ful green  color,  and  if  it  be  rendered  still  thinner,  either  by  beating,  or  by 
floating  it  upon  a  very  weak  solution  of  potassium  cyanide,  which  slowly 
dissolves  it,  it  transmits,  when  taken  upon  a  glass  plate  and  held  up  to  the 
light,  a  blue,  violet,  or  red  light,  in  proportion  as  its  thickness  diminishes. 
Even  when  it  is  so  transparent  that  one  may  read  through  it,  the  yellow 
color  and  luster  of  the  gold  arc  still  visible  by  reflected  light.  These  vary- 
ing colors  of  finely-divided  gold  are  turned  to  account  in  the  coloring  of 
glass  and  in  painting  on  porcelain." 


SILVER. 


167 


aqua  regia.  It  does  not  oxidize  at  any  temperature 
and,  on  account  of  the  resistance  it  offers  to  corro- 
sion, it  was  anciently  called  the  king  of  the  metals. 


SILVER 


Synjbol,  Ag  .  .  .  .  Aton^ic  Weight,108  ....  Specific  Gravity,  10.57. 
Fusiijg  Poiijt,  1904°  F.  or  1040°  C. 

Sources. — Silver  is  found  throughout  the  West  in 
a  great  variety  of  forms — most  commonly,  however, 

Fig.  66. 


Separation  of  Pb  from  Ag.    (See  Bloxarn''s  Metals.) 

combined  with    S,  as   black  sulphide,  AgaS  ;   with   CI, 
forming    horn-silver,    AgCl ;    with    S    and    As    or    Sb, 


168  INORGANIC    CHEMISTRY. 

making   ruby-silver,  and    also   associated  with    Pb   in 
ordinary  galena. 

Preparation. — 1st.  "The  suIpJdde  is  treated  as  fol- 
lows :  The  ore  is  crushed  into  fine  powder  and  then 
roasted  with  common  salt.  The  CI  of  the  salt  unites 
with  the  Ag,  forrfting  silver  chloride.  This  is  next 
put  into  a  revolving  cylinder  with  HgO,  Hg,  and  iron 
scraps.  The  Fe  removes  the  CI  from  the  silver,  when 
the  Hg  takes  it  up,  thus  forming  an  amalgam  of  Hg 
and  Ag.  From  this  the  Ag  is  easily  obtained  by  dis- 
tilling off  the  Hg,  as  in  the  extraction  of  gold.*  2d. 
From  horn-silver,  AgCl,  the  process  is  like  the  latter 
part  of  that  just  described.  3d.  From  lead  the  Ag  can 
be  profitably  obtained  when  there  are  only  two  or 
three  ounces  in  a  ton.  The  alloy  of  the  two  metals 
is  melted,  and  then  slowly  cooled.  Crystals  of 
almost  pure  Pb  appear,  and  are  skimmed  out  as  fast 
as  formed,  thus  leaving  an  alloy  much 
richer  in  silver.  (See  Fig.  GO.)  The 
last  portions  of  Pb  are  removed  from 
this  alloy  b}^  "  cupellation." 
"7  ,  ~  Cupellation.  —  A    cupel    {cupella,    a 

small  cup)  is  a  shallow  vessel,  made  of 
bone  ashes.  In  this  the  Ag,  debased  with  Pb  and 
other  impurities,  is  exposed  to  a  red  heat,  so  as  to 
melt   the   metals,   while    a   current   of   hot   air  plays 

*  "  The  process  of  reducing  silver  ores  at  the  West  is  unlike  the  German 
method  given  above,  and  varies  in  different  localities.  One  plan  is  as  fol- 
lows: The  powdered  and  roasted  AgjS  is  placed  with  Hg  in  iron  pans,  live 
feet  in  diameter  and  two  feet  deep.  Here  it  is  kept  heated  by  steam  to 
180°,  and  agitated  by  revolving  stirrers.  The  chloride  is  not  roasted,  but  is 
simply  powdered,  and  then  worked  in  the  pans  for  an  hour  with  NaCl  be- 
fore adding  the  Hg."— Stevenson. 


SILVER. 


169 


upon  the  surface.  The  Pb  oxidizes  to  PbO,  and  is 
absorbed  by  the  porous  cupel.  The  mass  appears 
soiled  and  tarnished,  but  the  refiner  keeps  his  eye 
upon  it  as  the  process  continues,  watching  eagerly, 
until  at  last  there  is  a  brilliant  play  of  colors — in  a 

Fig.  68. 


Cupels  in  the  Fm  nact. 


moment  more  the  last  film  of  oxide  disappears,  and 
the  brilliant  surface  of  the  pure  silver  lies  gleaming 
at  the  bottom.* 

*  See  Malachi  iii.  3.  During  the  cooling  of  the  cake  of  Ag,  some  very 
remarkable  phenomona  are  observed.  "When  a  thin  crust  of  metal  has 
formed  upon  the  surface,  the  Ag  beneath  it  assumes  the  appearance  of 
boiling,  and  the  crust  is  forced  up  into  hoUow  cones  about  an  inch  high, 
through  which  the  melted  Ag  is  thrown  out  with  explosive  violence,  some  of 
it  being  splashed  against  the  arch  of  the  furnace,  and  some  solidifying  into 
most  fantastic  tree-like  forms  several  inches  in  height.  This  behavior  of 
Ag  has  been  shown  to  be  due  to  its  proi)erty  of  mechanically  absorbing  O, 
at  a  temperature  above  its  melting-point,  which  it  gives  off  as  it  approaches 
the  point  of  solidification,  the  escaping  gas  forcing  up  the  crust  of  solid  Ag 
formed  upon  the  surface. 


170  -     INORGANIC     CHEMISTRY. 

Properties. — Ag  is  the  whitest  of  the  metals.  It  is 
malleable  and  ductile,  and  is  of  all  the  metals  the 
best  conductor  of  electricity.  It  expands  at  the 
moment  of  solidification,  and  therefore  can  be  cast. 
It  has  a  powerful  attraction  for  S,  forming  silver 
sulphide.  Silver  spoons  and  door-knobs  are  tarnished 
b}^  the  minute  quantities  of  H2S  present  in  the  air.* 
The  best  solvent  of  Ag  is  HNO3.  The  test  of  Ag  in 
solution  is  HCl,  which  forms  a  cloudy  precipitate  of 
silver  chloride.  A  solution  of  silver  coin  is  blue, 
from  the  Cu  it  contains.  Standard  silver  is  whitened 
by  being  heated  until  the  0  of  the  air  has  converted 
a  little  of  the  Cu  on  the  outside  into  CuO,  which  is 
dissolved  by  immersing  in  dilute  H2SO4.  or  NH4.OH. 
The  film  of  nearly  pure  Ag  which  then  remains  at  the 
surface  exhibits  a  want  of  luster  and  is  called  dead 
or  frosted  silver.     It  is  brightened  by  burnishing. 

Compounds.  —  Silver  Nitrate,  AgNOg,  is  sold  in 
small,  round  sticks  as  lunar  caustic,  used  as  a 
cautery.  It  stains  the  skin  and  all  organic  matter 
black,  especially  when  exposed  to  the  light,  owing 
to  the  formation  of  metallic  silver,  f  Many  hair-dyes 
and  indelible  inks  contain  AgNOs.     It  is  also  the  basis 

*  "  Those  who  have  visited  sulphiir  springs  know  the  propriety  of  care- 
fully protecting  their  watches,  and  of  never  wearing  silver  ornaments  to 
the  hot  baths.  AgoS  is  very  easily  dissolved  by  a  little  dilvte  ammonia 
(1  part  of  NH.OH  to  20  of  HnO),  which  is  therefore  used  for  cleaning  silver 
door-knobs.— ftrirfi2«<?  sliver,  as  it  is  erroneously  called,  is  made  by  immers- 
ing articles  of  silver  in  a  solution  obtained  by  boiling  siilphur  with  potash, 
when  the  metal  becomes  coated  with  a  thin  film  of  sulphuret  of  silver." — 
Bloxah. 

t  The  stain  of  silver  nitrate  may  be  removed  by  a  strong  solution  of 
potassium  iodide  or  the  poisonous  potassium  cyanide.  (See  caution  on  page 
290.) 


SILVER.  171 

of  photography  (light-drawing)  and  daguerreotyping  * 
which  are  both  founded  upon  essentially  the  same 
principles.  The  general  outlines  of  the  photographic 
process  are  as  follows:  1.  Iodized  collodion f  is  poured 
upon  a  clean  glass  plate,  which,  on  evaporation,  it 
covers  with  a  transparent  film.  2.  The  plate  is  put 
in  the  "nitrate  of  silver  bath,"  t  where  the  salt  of 
silver  is  absorbed  by  the  collodion  film  and  changed 
to  brom-iodide  of  silver.  The  plate  is  now  ready  for 
the  picture.  After  the  sitting,  the  plate  is  taken, 
carefully  protected  from  the  light,  to  the  operator's 

*  The  dagrueiTeotjT)e  is  named  from  M.  Daguerre,  the  discoverer,  who 
received  a  pension  of  6,000  francs  per  year  from  the  French  government. 
A  plate  of  Cu,  plated  on  one  side  with  Ag,  is  exposed  to  the  vapor  of  I  and 
Br  until  a  compound  of  brom-iodide  of  silver  is  formed  upon  the  surface. 
This  is  extremely  sensitive  to  the  light,  hence  the  process  is  always  con- 
ducted in  a  dark  closet.  The  plate  is  then  carried,  carefully  covered,  to  the 
camera,  and  placed  in  the  focus,  where  the  rays  of  light  from  the  person 
whose  "  picture  is  being  taken  "  fall  directly  upon  it.  These  rays  decompose 
the  brom-iodide  of  silver.  The  amount  of  this  change  is  directly  proportional 
to  the  intensity  of  the  light  that  is  reflected  from  different  parts  of  the 
person  to  form  the  image  in  the  camera.  A  white  garment  reflects  much 
of  the  light  that  falls  upon  it,  so  the  coiTesponding  part  of  the  plate  will 
be  very  much  changed.  A  black  garment  reflects  but  little  light,  so  that 
part  will  ncrt  be  changed  at  all.  The  different  colors  and  shades  reflect 
varying  proportions  of  light,  and  so  influence  the  plate  correspondingly. 
When  the  plate  is  taken  out  of  the  camera,  it  is  carefully  covered  again  and 
can'ied  into  the  dark  closet.  No  change  can  be  detected  by  the  eye;  but 
on  exposure  to  the  vapor  of  Hg,  wherever  the  Ag  has  been  freed,  the  Hg 
will  combine  with  it,  forming  a  whitish  amalgam,  but  it  has  no  effect  on 
the  rest  of  the  plate.  The  picture  thus  treated  comes  forth  nearly  perfect 
in  its  lights  and  shades.  The  undecomposed  brom-iodide  of  silver  is  re- 
moved by  a  solution  of  sodium  hjTiosulphite.  A  solution  of  gold  chloride 
and  sodium  hyposulphite  is  then  poured  upon  the  plate  and  warmed.  This 
golden  varnish  finishes  the  picture. 

+  Iodized  collodion  is  composed  of  gun-cotton  dissolved  in  alcohol  and 
ether,  to  which  are  added  ammonium  iodide  and  cadmium  bromide,  or 
similar  salts. 

t  The  nitrate  of  silver  bath  contains  nitrate  of  silver  and  iodide  of  silver 
in  solution,  and  is  acidulated  with  nitric  acid. 


172  INORGANIC     CHEMISTRY, 

room.  Here  the  picture  is,  3,  developed  by  a  solution 
of  ferrous  sulphate  (green  vitriol,  see  p.  158)  or  pyro- 
gallic  acid  (see  p.  238) ;  at  the  right  stage  the  liquid 
is  washed  off,  and  the  operation  checked.  4.  It  is 
fixed  with  a  solution  of  sodium  hyposulphite,  which 
dissolves  the  unaltered  brom-iodide  of  silver.  5.  It  is 
washed,  dried,  and  coated  with  amber  varnish  to 
preserve  the  film  from  accidental  injury.  The 
*'  negative "  is  now  completed,  and  is  a  correct  like- 
ness, only  the  lights  and  shades  are  reversed.  From 
this  the  pictures  are,  1,  "printed"  by  placing  the 
negative  upon  a  sheet  of  prepared  paper,*  and  expos- 
ing it  to  the  sun's  rays.  When  the  colors  are  suffi- 
ciently deepened,  the  picture  is,  2,  toned  in  the 
"toning-bath,"  which  contains  a  little  ''bicarbonate 
of  soda"  and  a  minute  quantity  of  gold  chloride; 
3,  fixed,  by  sodium  hyposulphite  which  dissolves  the 
unaltered  AgCl ;  4,  thoroughly  washed  in  water  fre- 
quently renewed ;  and,  lastly,  dried  and  mounted  on 
card-board.  The  thoroughness  of  the  third  and  fourth 
processes  has  much  to  do  with  the  permanence  of 
the  picture.  If  any  of  the  chloride  or  the  compound 
formed  by  the  hyposulphite  be  left,  it  will  cause 
fading  or   discoloration. 

Silver  Chloride,  AgCl,  occurs  naturally  as  horn- 
silver,  and  falls  as  a  white  curdy  precipitate  when 
HCl  or  a  soluble  chloride  {e.  g.,  NaCl)  is  mixed  with  a 
silver  SDlution. 

♦  This  paper  is  "  sensitized "  by  floating  it  on  a  solution  of  sodium 
chloride,  and  then  on  one  of  silver  nitrate,  thus  filling  the  pores  of  the 
paper  with  the  silver  chloride,  which  ia  extremely  sensitive  to  light. 


PLATINUM.  173 

P  L  AT  I  N  U  M. 

Synjbol,  Pt. ...  Atonjic  Weight,  194.3  ....  Specific  Gravity,  21.53. 
Fusing  Point,  about  3632°  F.  or  2000''^  C. 

Source. — Pt*  is  chiefly  found  in  the  Ural  Mount- 
ains, where  it  occurs  in  alluvial  deposits,  usually  in 
small,  flattened  grains,t  which  contain  Au,  Pd,  Rh, 
Ru,  Ir,  and  Os,  as  well  as  Fe,  Cu,  etc.,  besides  the  Pt. 

Preparation. — The  "ore,"  as  it  is  called,  is  sepa- 
rated from  the  earthy  particles  by  washing,  and  the 
Pt  extracted  by  a  rather  complicated  process. 

Properties. — Pt  resembles  Ag  in  its  appearance.  It 
is  one  of  the  most  ductile  metals,  wire  having  been 
made  from  it  so  fine  as  to  be  invisible  to  the  naked 
eye.  J  It  is  soluble  in  aqua  regia,  but  not  in  the  simple 
acids.  It  does  not  oxidize  in  the  air,  is  one  of  the 
most  infusible  of  metals,  and  can  be  melted  only  by 
the  heat  of  the  compound  blow-pipe  or  voltaic 
battery.  In  the  arts  it  is  fused  in  the  former 
manner.  These  properties  fit  it  for  making  crucibles 
that  are  invaluable  to  the  chemist. 

Platinum  Sponge  (see  page  42)  is  made  by  heat- 
ing the  double  chloride  of  Pt  and  NH4. 

Platinum  Black  is  obtained  by  the  action  of  re- 
ducing agents  upon  Pt  solutions. 

*  The  word  platinum  signifies  "  little  silver." 
t  The  largest  nugget  ever  found  weighed  about  18  lbs. 
t  WoUaston's  Method,  as  it  is  called,  consists  in  covering  fine  platinum 
wire  with  several  times  its  weight  of  Ag,  and  then  drawing  this  through 
the  plates  used  for  drawing  wire  until  the  finest  hole  is  reached,  when  the 
wire  is  placed  in  HNO3,  which  dissolves  the  Ag  and  leaves  the  Pt  intact. 
This,  in  the  form  of  the  finest  wire  known,  may  be  found  in  the  solution 
by  means  of  a  microscope.    (See  "Physics,"  p.  19.) 


174  INORGANIC     CHEMISTRY. 


MERCURY. 

Symbol,  Hg  .  .  .  .  Atonjic  Weight,  200  ...  .  Specific  Gravity,  13.6. 
Melting  (Freeziijg)  Poiijt,— 39°  C Boiiiijg  Poiijt,  680°  F.  or  360°  C. 

Mercury  is  also  called  quicksilver,  because  it  rolls 
about  as  if  it  were  alive,  and  was  supposed  by  the 
alchemists  to  contain  silver.  It  was  known  very 
anciently,  and  the  mines  of  Spain  were  worked  by 
the  Romans. 

Source. — Cinnabar,  HgS,  a  brilliant  red  ore,  is  the 
principal  source  of  this  metal.* 

Preparation. — Hg  is  readily  prepared  by  heating 
HgS  in  a  current  of  air.  The  S  passes  off  as  SO2,  while 
the  Hg  volatilizes  and  is  condensed  in  earthen  pipes. 

Properties. — Hg  emits  a  vapor  at  all  temperatures, 
and  this  vapor  is  poisonous.  The  solvent  of  Hg  is 
HNO3.  It  forms  an  amalgam  f  with  gold  or  silver. 
This    is    its    most    singular    property.      A    gold    leaf 

*  Hg  is  found  native  in  Mexico  in  very  small  quantities,  where  the 
mines  are  said  to  have  been  discovered  by  a  slave,  who,  in  climbing  a 
mountain,  came  to  a  very  steep  ascent.  To  aid  him  in  surmounting  this, 
he  tried  to  draw  himself  up  by  a  bush  which  grew  in  a  crevice  above.  The 
shrub,  however,  giving  way,  was  torn  up  by  the  roots,  and  a  tiny  stream, 
of  what  seemed  liquid  silvei',  trickled  down  upon  him. 

+  "  Several  years  ago.  while  lecturing  upon  chemistry  before  a  class  of 
ladies,  wo  had  occasion  to  purify  some  quicksilver  by  forcing  it  through 
chamois  skin.  The  scrap  of  leather  remained  upon  the  table  after  the 
iectui-e,  and  an  old  lady,  thinking  it  would  be  very  nice  to  WTap  her  gold 
spectacles  in,  accordingly  appropriated  it  to  this  purpose.  The  next  morn- 
ing she  came  to  us  in  great  alarm,  stating  that  tlie  gold  had  mysteriously 
disappeared,  and  nothing  was  left  in  the  parcel  but  the  glasses.  Sure 
enough,  the  metal  remaining  in  the  pores  of  the  leather  had  amalgamated 
with  the  gold,  and,  entering,  destroyed  the  spectacles.  It  was  a  mystery, 
however,  which  we  could  never  explain  to  her  satisfaction."— J.  R.  Nichols 
in  Fireside  Science. 


MERCURY.  175 

dropped  upon  mercury  disappears  like  a  snow-flake 
in  water.  Particles  of  Ag  or  Au,  too  fine  to  be  seen  by 
the  eye,  will  be  found  by  Hg  and  gathered  from  a 
mass  of  ore. 

Uses. — Hg  is  extensively  employed  in  the  manu- 
facture of  thermometers  and  barometers  ;  for  silver- 
ing mirrors ;  *  and  for  extracting  the  precious  metals 
from  their  ores. 

The  action  of  Hg  on  the  human  system  is  too 
well  known  to  need  description.  "In  its  metallic 
state,  Hg  has  been  taken  with  impunity  in  quantities 
of  a  pound  weight"  ("American  Cyclopaedia"),  but 
when  finely  divided,  as  in  vapor,  mercurial  ointnient,t 
or  "blue-pill,"  its  effects  are  marked.  It  renders  the 
patient  extremely  susceptible  to  colds ;  acts,  as  is 
generally  thought,  upon  the  liver,  increasing  the  se- 
cretion of  bile,  and  repeated  doses  produce  "salivation." 

Compounds. — Mercuric    Oxide,  HgO,  "red  precipi- 

*  Mirrors  were  anciently  made  of  steel  or  silver,  highly  polished.  They 
were  very  liable  to  rust  and  tarnish,  and  so  a  piece  of  sponge,  sprinkled 
with  pumice-stone,  was  suspended  from  the  handle  for  rubbing  the  mirror 
before  use.  Seneca,  in  lamenting  over  the  extravagance  of  his  time  among 
the  old  Romans,  says :  "  Every  young  woman  nowadays  must  have  a  silver 
mirror."  The  process  of  "silvering"  ordinary  mirrors  is  briefly  as  follows: 
Tin-foil  is  first  spread  evenly  iipon  a  marble  table,  and  then  the  Hg  is  care- 
fully poured  over  it.  The  two  metals  combine,  forming  a  bright  amalgam. 
A  clean,  dry  plate  of  glass  is  then  carefully  pushed  forward  over  the  table 
so  as  to  carry  the  superfluous  Hg  before  it,  and  also  prevent  the  air  from 
getting  between  the  glass  and  the  amalgam.  Weights  are  afterward  added 
to  cause  the  fllm'to  cling  more  closely.  In  twenty-four  hours  the  plate  is 
removed,  and  in  three  or  four  weeks  is  dry  enough  to  be  framed.  Wlaen 
we  look  in  a  mirror  we  rarely  realize  what  it  has  cost  others  to  thus 
minister  to  our  comfort.  The  workmen  are  short-lived.  A  paralysis  some- 
times attacks  them  within  a  few  weeks  after  they  enter  the  manufactory. 
Silver  is  now  often  used  in  backing  mirrors.    It  is  harmless. 

t  This  is  vulgarly  called  "  anguintum,"  which  may  be  a  corruption  of 
the  Latin  term  unguentum  (unguent).    It  is  used  in  cutaneous  diseases. 


176  INORGANIC     CHEMISTRY. 

tate,"  is  interesting,  as  the  substance  from  which 
Priestley  first  obtained  0  gas. 

Mercurous  Chloride,  HgCl,  Calomel,  is  a  white 
powder  used  in  medicine.  It  can  be  easily  distin- 
guished from  corrosive  sublimate,  since  it  is  insoluble 
in  HgO,  and  hence  tasteless. 

Mercuric  Chloride,  HgCl2,  Corrosive  Sublimate,  is 
a  heavy,  white  solid,  soluble  in  HjO,  and  has  a 
burning  metallic  taste.  It  has  powerful  antiseptic 
properties,  and  is  used  to  preserve  specimens  in 
natural  history.  It  is  a  deadly  poison.  Its  antidote 
is  white  of  eggs,  milk,  etc. 

Mercuric  Sulphide,  HgS,  "  Vermilion,''''  is  made  by 
subliming  a  previously  fused  mixture  of  Hg  and  S. 
It  is  used  as  a  pigment. 


THE     ALLOYS. 

These  are  very  numerous,  and  many  of  them  pos- 
sess properties  so  different  from  their  elements  that 
they  seem  like  new  metals.  The  color  and  hard- 
ness are  changed,  and  sometimes  the  melting  point 
is  below  that  of  any  one  of  the  constituents.  The 
proportions  of  the  metals  used  vary.  The  following 
is  a  fair  average : 

Type-metal*  contains  50  per  cent,  of  Pb,  equal 
parts  of  Sn  and  antimony,t  and  a  little  Cu. 

*  Tho  composition  of  tyije-inetal  varies  considerably.  It  is  sometimes 
made  of  Pb  and  antimony  alone ;  and  the  proportions  of  these  two  metals 
are  different  for  large  and  small  t.\T)e— the  small  t^-pe  containing  a  larger 
amount  of  antimony  to  make  them  harder. 

t  Antimony  was  discovered  by  Basil  Valentine,  a  monk  of  Germany,  in 


THE     ALLOYS.  177 

Pewter  contains  9  parts  of  Sn  and  1  of  Pb. 

Britannia  consists  of  9  parts  of  Sn,  1  of  Sb,  and 
usually  about  3  per  cent.  Zn,  and  1  per  cent.  Cu. 

Brass  is  about  2  parts  of  Cu  and  1  of  Zn. 

German  Silver  contains  50  parts  of  Cu,  25  of  Zn, 
and  25  of  Ni*  (brass  whitened  by  nickel). 

Soft  Solder,  used  by  tinsmiths,  is  made  by  melt- 
ing Pb  and  Sn  together,  the  usual  proportion  being 
half-and-half. 

Hard  Solder  is  composed  of  Cu  and  Zn, 

Wood's  Fusible  Metal  melts  at  158°  F. ;  and 
spoons  made  of  it  will  fuse  in  hot  tea.  It  can  be 
melted  in  a  paper  crucible  over  a  candle.  It  consists 
of  Bi,f  Pb,  Sn,  and  Cd.  Yet  the  first  metal  melts  at 
518°  F.,  the  second  at  635°,  the  third  at  446°,  and 
the  fourth  at  599°. 

Bronze  is  3  parts  of  Cu  and  1  part  of  Sn. 

Gold  is  soldered  with  an  alloy  of  itself  and  Ag ; 
Silver,  with   itself  and   Cu ;   Copper,   with   itself  and 

the  fifteenth  century.  It  is  a  brittle,  bluish-white  metal,  with  a  beautiful 
laminated,  star-like,  crystalline  structure.  Its  chief  use  is  as  an  alloy  for 
type-metal,  Britannia-ware,  etc.,  one  of  its  most  important  properties  being 
that  it  expands  in  c  oling  from  "usion,  and  thus  makes  a  very  sharp  cast- 
ing. Its  test  is  HoS,  which  throws  down  u  brilliant  orange-colored  precip- 
itate. Melt  a  small  fragment  of  Sb  before  the  blow-pipe,  and  throw  the 
melted  globule  upon  an  inclined  plane.  It  will  instantly  dart  off  in  minute 
spheres,  each  followed  by»a  long  trail  of  smoke. 

*  Ni,  like  Co,  is  a  constituent  of  meteorites.  It  is  mined  in  Pennsyl- 
vania, Canada,  New  Caledonia,  etc.,  to  make  into  coins.  Formerly,  its 
principal  use  was  in  German  silver,  but  of  late  it  has  been  employed  ex- 
tensively in  the  manufacture  of  the  best  plated-ware.  (See  "  Physics,"  page 
238.)  Its  silvery  whiteness,  when  pure,  its  high  polish,  which  often  lasts  for 
years,  and  its  hardness,  almost  equal  to  tliat  of  steel,  eminently  fit  it  for  the 
plating  of  mathematical  and  other  delicate  instruments.  The  salts  of  Ni 
have  a  handsome  green  tint. 

t  Bismuth  closely  resembles  Sb.  Its  chief  use  is  in  making  fusible 
alloys.     Its  salts  are  employed  in  making  cosmetics  and  as  medicines. 


178  INORGANIC     CHEMISTRY. 

Zn :  the  principle  being  that  the  metal  of  lower 
fusing  point  causes  the  other  to  melt  more  easily. 

Coin. — The  precious  metals,  when  pure,  are  too 
soft  for  common  use.  They  are  therefore  hardened 
by  other  metals.  The  gold  coin  of  the  United  States 
consists  of  9  parts  of  gold  and  1  of  alloj^  The  alloy 
is  chiefly  Cu  ;  but  gold  coin  always  contains  a  little 
Ag,  which  was  not  separated  from  the  Au  in  the 
quartation  (p.  166).  Silver  coin  is  9  parts  of  Ag  and 
1  of  Cu.  The  nickel  coin  is  75  parts  of  Cu  and  25 
of  Ni.  Cu  being  cheaper  than  Ni,  it  is  used  to  make 
the  coin  larger.  The  term  carat ^  applied  to  the 
precious  metals,  means  -^^  part.  Therefore,  gold  18 
carats  fine  contains  |f  of  gold  and  /f  of  alloy. 

Shot  is  an  alloy  of  something  less  than  1  part  of 
As  to  100  of  Pb.  The  manufacture  is  carried  on  in 
what  are  called  "shot-towers,"  some  of  which  are  two 
hundred  and  fifty  feet  high.  The  alloy  is  melted  at 
the  top  of  the  building,  and  poured  through  colan- 
ders. The  metal,  in  falling,  breaks  up  into  drops, 
which  take  the  spherical  form  (see  "Physics,"  pages 
44  and  192),  harden,  and  are  caught  at  the  bottom 
in  a  well  of  water,  which  cools  the  shot  and  also 
prevents  their  being  bruised  in  striking.  The  shot 
are  dipped  out,  dried,  and  then  assorted,  by  sifting 
in  a  revolving  cylinder,  which  is  set  slightly  inclined 
and  perforated  with  holes,  increasing  in  size  from  the 
top  to  the  bottom.  The  shot  being  poured  in  at  the 
top,  the  small  ones  drop  through  first,  next  the  larger, 
and  so  on,  till  the  largest  reach  the  bottom.  Each 
size  is  received  in  its  own  box.    Shot  are  polished  by 


REVIEW     OF     THE     METALS.  179 

being  agitated  for  several  hours  with  black-lead,  in  a 
rapidly-revolving  wheel.  They  are  finally  tested  by 
rolling  them  down  a  series  of  inclined  planes  placed 
at  a  little  distance  from  each  other.  The  spherical 
shot  will  jump  from  one  plane  to  the  next,  while  the 
imperfect  ones  will  fall  short,  and  drop  below ;  or 
soinetimes,  by  rolling  down  a  single  inclined  plane, 
the  spherical  ones  will  go  to  the  bottom,  while  the 
imperfect  ones  roll  off  at  the  sides. 

Or-Molu  is  a  beautiful  alloy  of  Cu  and  Zn  resem- 
bling red  gold,  but  it  soon  tarnishes  by  exposure  to 
the  air. 

Aluminium  Bronze,  or  gold,  is  an  alloy  of  Al  and 
Cu.  It  is  elastic,  malleable,  and  very  light.  It 
strikingly  resembles  gold,  and  is  sometimes  used  in- 
stead of  that  costly  metal.  • 


REVIEW  OF  THE  PROPERTIES 
OF  THE  METALS. 

Oxidation. — K  and  Na  have  an  intense  attraction 
for  0  and  other  elements,  and  are  never  found  ex- 
cept in  combination,  while  Au,  Pt,  etc.,  have  little 
affinity  for  other  substances,  and  are  therefore  found 
native. 

Density. — Li  is  lighter  than  any  known  liquid.  K, 
Na,  and  Li  float  upon  H2O,  while  Pt  is  over  twenty- 
one  times  and  Os  over  twenty-two  times  as  heavy  as 
H2O. 

Melting  Point. — Hg  is  liquid  at  all  ordinary  tem- 
peratures.    K  and  Na  melt  beneath  the  boiling  point 


180  INOEGANIC     CHEMISTRY, 

of  H2O  ;  Zn  below  a  red  heat,  and  Cu  above;  Co,  Ni, 
and  wrought  iron  reqidre  the  greatest  lieat  of  the 
forge  (-±000°  ¥.),  while  Pt  and  Os  melt  only  in  the 
flame  of  the  oxy-hydrogen  blow-pipe.  Sn  melts  at 
the  lowest  temperature  (446°)  of  any  of  the  ordinary 
metals. 

Color. — The  most  common  color  is  white,  of  vary- 
ing shades.  It  is  nearly  pure  in  Ag,  Pt,  Cd,  and  M.g  ; 
yellowish  in  Sn ;  bluish  in  Zn  and  Pb ;  gray  in  Fe, 
and  reddish  in  Bi.  Cu  is  a  full  red,  and  Au  a  bright 
yellow. 

Malleability. — Au,  Ag,  Al,  and  Cu  are  the  most  malle- 
able of  the  metals;  Au,  Ag,  and  Pt  are  the  most  ductile. 

Brittleness. — Sb  and  Bi  may  be  easily  powdered  ; 
Zn  may  be  broken  with  more  difficult}',  while  the 
fibrous  inetals  are  exceedingly  tough. 

Tenacity. — Steel  is  the  most,  and  lead  the  least, 
tenacious  of  the  metals ;  the  proportion  being  as 
1  to  42. 

Special  Properties.  —  Certain  of  the  metals  are 
valuable  because  of  their  peculiar  properties.  Thus, 
Hg,  because  it  will  form  an  amalgam,  and  is  a  liquid 
at  all  ordinary  temperatures ;  Sb,  because  it  hardens 
Pb  and  Sn  ;  Bi  and  Cd,  because  they  render  Pb  and 
Sn  more  fusible  ;  Ni,  because  it  whitens  Cu  ;  Mg,  for 
its  brilliant  light :  Au,  for  its  rarity  and  luster ;  Fe, 
for  the  diverse  properties  it  can  assume  in  "wrought 
and  cast  iron  and  in  steel,  and  because  it  is  the  only 
metal  which  can  be  used  for  the  magnetic  needle 
and  electro-magnet ;  Cu,  for  its  ductility  and  its  con- 
ductivity of  electricity ;   and  Pt,  for  its  infusibility. 


PRACTICAL     QUESTIONS.  181 


PRACTICAL    QUESTIONS. 

1.  Pb  is  softer  than  Fe ;  why  is  it  not  more  malleable  ? 

2.  "WTiat  is  the  cause  of  the  changing  color  often  seen  in  the  scum  on 
standing  water? 

3.  How  can  the  spectra  of  the  metals  be  obtained? 

4.  Ought  cannon,  car-axles,  etc.,  to  be  used  until  they  break  or  wear 
out? 

5.  Wliy  is  "chilled  iron"  used  for  safes? 

6.  Does  a  blacksmith  plunge  his  work  into  water  merely  to  cool  it? 

7.  What  causes  the  white  coating  made  when  we  spill  water  on  zinc? 

8.  Is  it  well  to  scald  pickles,  make  sweetmeats,  or  fry  cakes  in  a  brass 
kettle  ? 

9.  What  danger  is  there  in  the  use  of  lead  pipes?    Is  a  lining  of  Zn  or 
Sn  a  protection? 

10.  Is  water  which  has  stood  in  a  metal-lined  ice-pitcher  healthful? 

11.  If  you  ask  for  "cobalt"  at  a  drug-store,  what  will  you  get?  If  for 
"  arsenic  "  ? 

12.  WTiat  two  elements  are  fluid  at  ordinary  temperatures? 

13.  Should  we  touch  a  gold  ring  to  mercury?* 

14.  WTiy  does  silver  blacken  if  exposed  to  the  air? 

15.  Why  does  silver  tarnish  more  rapidly  where  coal  is  used  for  fires? 

16.  Why  is  a  solution  of  a  silver  coin  blue? 

17.  Why  "will  a  solution  of  silver  nitrate  curdle  brine? 

18.  Wliy  does  writing  with  indelible  ink  turn  black  when  exposed  to 
the  sun,  or  to  a  hot  iron? 

19.  What  alloys  resemble  gold? 

20.  Why  does  a  fish-hook  "rust  out"  the  line  to  which  it  is  fastened? 

21.  VThy  do  the  nails  in  clapboards  loosen? 

22.  Show  that  the  earth's  crust  is  mainly  composed  of  burnt  metals. 

23.  "\^Tiat  kind  of  iron  is  used  for  an  electro-magnet?  For  a  magnetic 
needle  ? 

24.  Wliy  does  a  "tin"  pail  so  quickly  rust  out  when  once  the  tin  is 
worn  through? 

25.  Why  is  the  zinc  oxide  found  in  Xew  Jersey  red,  when  zinc  rust  is 
white? 

26.  Should  we  filter  a  solution  of  permanganate  of  jwtash  throiigh 
paper? 

27.  Why  are  wood,  cordage,  etc.,  sometimes  soaked  in  a  solution  of  cor- 
rosive sublimate? 

28.  "Why  does  the  white  paint  around  a  sink  sometimes  tiirn  black? 
What  danger  does  this  indicate? 

*  If  the  surface  is  only  whitened,  the  Hg  may  be  removed  with  dilute 
HNOa,  and  the  ring  be  polished  to  look  as  before.  The  Hg  will  soon  pene- 
trate the  gold,  and  render  it  brittle. 


182  INORGANIC     CHEMISTRY. 

29.  Why  is  aluminium,  rather  than  platinum,  sometimes  used  for 
making  the  smallest  weights? 

30.  How  would  you  detect  the  presence  of  iron  particles  in  black  sand? 

31.  "Which  metals  can  be  welded? 

32.  "When  the  glassy  slag  from  a  blast-furnace  has  a  dark  color,  what 
does  it  show? 

33.  In  welding  iron,  the  surfaces  to  be  joined  are  sometimes  sprinkled 
with  sand.    Explain. 

34.  What  is  the  difference  between  an  alloy  and  an  amalgam? 

35.  Steel  articles  are  blued  to  protect  from  rusting,  by  heating  in  a 
sand-bath.    Explain. 

36.  Give  the  formulas  for  coppei'as  and  white  lead. 

37.  Why  is  Hg  used  for  filling  thermometers? 

38.  What  oxides  are  formed  by  the  combustion  of  Na,  K,  Zn,  S,  Fe,  Pb, 
Cu,  P,  etc?  Wliich  are  bases?  Anhydrides?  Give  the  common  name  of 
each. 

39.  Is  charcoal  lighter  than  H..O? 

40.  Name  the  "vitriols." 

41.  Is  Mg  univalent  or  bivalent?    Zn? 

42.  Name  some  bibasic  acid. 

43.  Name  a  neutral  salt.    An  acid  salt. 

44.  Calculate  the  percentage  of  water  contained  in  crystallized  copper 
sulphate ;  in  sodium  sulphate ;  in  calcium  sulphate  ;  in  alum. 

45.  What  is  the  test  for  Ag?    Cu? 

46.  Wliat  weight  of  crystallized  "tin  salts"  (SnCl2,2IT»0)  can  be  pre- 
pared from  one  ton  of  metallic  tin? 

47.  100  parts  by  weight  of  silver  yield  132.87  parts  of  silver  chloride. 
Given  the  atomic  weight  of  chlorine  (35.5),  reqiured  that  of  silver. 

48.  What  is  the  composition  of  sl.ikod  lime? 

49.  How  is  ferrous  sulphate  obtained?  How  many  tons  of  crystals  can 
be  obtained  by  the  slow  oxidation  of  230  tons  of  iron  pjTites  containing 
37.5  per  cent,  of  sulphur? 

50.  Required  500  tons  of  soda  crystals;  what  will  be  the  weight  of  salt 
and  pure  sulphiiric  acid  needed? 

51.  Describe  the  uses  of  lime  in  agriculture. 

52.  How  many  tons  of  oil  of  vitriol,  containing  70  per  cent,  of  pure 
acid  (H3SO,),  can  be  prepared  from  250  tons  of  iron  pyrites,  containing  42 
per  cent,  of  sulphur? 


Ill 


Organic  Chemistry 


'  Thus  the  Seer, 
With  vision  clear, 
Sees  forms  appear  and  disappear. 
In -the  perpetual  round  of  strange. 
Mysterious  change 

From  birth  to  death,  from  death  to  birth. 
From  earth  to  heaven,  from  heaven  to  earth; 
Till  glimpses  more  sublime 
Of  things,  unseen  before, 
Unto  his  wondering  eyes  reveal 
The  Universe  as  an  immeasurable  wheel 
Turning  forevermore 
In  the  rapid  and  rushing  river  of  Time." 

Longfellow. 


ORGANIC  CHEMISTRY. 


INTRODUCTION. 

Organic  Chemistry  is  the  chemistry  of  the  com- 
pounds of  carbon.  It  originally  meant  the  chemistry 
of  organized  bodies,  animal  and  vegetable,  and  their 
products.  As  was  stated  in  the  introduction  (p.  7), 
it  was  formerly  believed  that  the  so-called  organic 
substances  formed  a  group  entirely  distinct  from  the 
inorganic,  because  they  could  be  produced  only  by 
the  agency  of  life.  But  in  1828,  Wohler,  a  German 
chemist,  discovered  that  an  organic  compound,  urea, 
could  be  artificially  prepared.  Since  then  a  very 
large  number  of  compounds  have  been  made,  which 
had  before  been  obtained  only  from  animal  and 
vegetable  substances ;  among  others  such  well-known 
ones  as  alcohol,  tartaric  acid,  glycerin,  indigo,  aliza- 
rin (the  coloring  matter  of  madder),  and  gallic  acid.* 

There  is,  however,  one  class  of  organic  substances, 
the  organized  bodies,  such  as  muscular  tissue,  nerve 
structure,  ligneous  fiber,  no  one  of  which  has  yet 
been  made  in  the  chemist's  laboratory ;  nor  is  there 
any  promise  in  the  past  development  of  organic 
chemistry,  wonderful  as  that  development  has  been, 

*  "There  is  but  little  doubt,  as  new  methods  are  discovered,  and  our 
knowledge  of  the  carbon  compounds  increase,  that  we  may  eventually  be 
able  to  produce  synthetically  even  the  most  complex.''— Miller. 


186  ORGANIC     CHEMISTRY. 

that  these  substances  can  be  artificially  made.  These 
organized  bodies  are  formed  frorn  inanimate  matter, 
by  the  action  of  life,  and  are  constantly  under- 
going rapid  change. 

While  other  substances  are  formed  and  remain 
fixed  in  one  state  under  the  influence  of  chemical 
affinity,  the"  organized  bodies  grow  rapidly,  change 
constantly,  and  when  life  ceases,  as  rapidly  decay. 
Owing  to  their  complex  structure,  and  the  presence 
in  many  of  them  of  the  negative  N,  they  form  most 
unstable  compounds.  In  this  we  find  the  cause  of 
their  quick  decay.  The  vital  principle  alone  holds 
them  together,  and  the  instant  that  is  removed,  dis- 
integration sets  in,  the  tendency  of  the  component 
elements  being  to  seek  new  affinities  and  form  new 
compounds. 

Composition  of  Organic  Substances. — All  organic 
substances  contain  C.  One  large  and  important  class 
contain  C  and  H  alone  ;  many  consist  of  the  three 
elements  C,  H,  and  0  ;  others  consist  of  C,  H.  0,  and 
N  ;  while  a  few  contain  also  S  and  P.  In  the  labo- 
ratory, organic  compounds  have  been  made  which 
contain  many  other  elements ;  but  those  given  above 
exhaust  the  variety  of  elementary  constitution  in 
most  natural  organic  substances. 

The  Number  of  Carbon  Compounds  greatly  ex- 
ceeds that  of  all  the  other  substances  combined,  and  is 
constantly  increasing.  The  labor  of  modern  chemists 
is  largely  devoted  to  the  subject,  and  the  field  opens 
and  broadens  with  every  discovery.  That  such  a  vast 
number  of  different  compounds  of   carbon  with  two 


INTRODUCTION.  187 

or  three  other  elements  should  exist,  seems  at  first 
very  puzzling.  In  inorganic  chemistry,  the  number 
of  compounds  which  any  single  element  can  form 
with  all  the  others,  is  veiy  limited.  The  explanation 
must  be  looked  for,  first  of  all,  in  a  peculiarity  of  C. 
We  have  already  learned  that  C  is  quadrivalent, 
forming  a  compound  with  four  atoms  of  H, —  CH4.  If 
we  use  a  dash  to.  indicate   each  unit  of  valence,  this 

formula  may  be  written : 

H 

C  =  H4,  or  H-C-H. 

I 
H 

Another  compound  of  C  and  H  is  CaHg.  The  only 
way  in  which  this  can  be  expressed  in  detail,  ac- 
counting for  the  quadrivalency  of   C   in  both  atoms, 

is  H3=C-C=H3,  or 

H 

H-C-H 
H-C-H 

{^ 

which  shows  the  C  atoms  linked  together  by  one 
dash  or  "  bond  "  of  valence,  and  thus  capable  of  hold- 
ing three,  and  only  three,  atoms  of  H  apiece.  In  the 
same  way,  CsHg  equals  H3=C-C=H2-C=H3 ;  C4H10  equals 
C=H3-C=H2-C=H2-C=H3,  etc. 

l\\  another  series  of  hydrocarbons,  a  linkage  be- 
tween two  atoms  of  C  by  double  bonds  occurs  ;  thus, 
C2H4.  (see  p.  72),  equals  H2=C~C=H2  ;  CsHg  equals  H^^ 
C=C-H-C=H3,  etc.  In  still  another  series,  there  is  a  link- 
age by  three  bonds  ;   thus,  C2H2  equals  H-C=C-H,  etc. 


1^8  O  K  (1 A  X  I C     C  H  E  M  I  S  T  K  Y  . 

It  is  through  this  facihty  with  which  C  atoms 
link  together  in  chains,  that  the  number  of  different 
organic  compounds  is  in  part  explained.  When  we 
consider  further  that  one  or  more  H  atoms  in  each 
of  these  hydrocarbons  may  be  replaced  by  0,  N,  or 
groups  containing  0,  N,  H,  and  C,  such  as  OH,  NOg, 
CO,  NHg,  CN,  CH3,  etc.,  etc.,  the  great  variety  of  or- 
ganic substances  ceases  to  be  so  surprising. 

Isomerism. — Isomeric  compounds  are  those  which 
consist  of  the  same  elements  in  the  same  proportion. 
Thus  two  compounds  are  known  which  have  the 
same  formula,  C2H4CI2,  and  there  are  many  similar 
cases.  The  difference  between  such  compounds  is 
believed  to  lie  in  a  dissimilar  grouping  of  the  atoms 
about  one  another,  as  the  same  pieces  upon  a 
checker-board  may  be  variously  arranged ;  or  as  the 
letters  p-l-e-a  may  also  spell  1-e-a-p,  or  p-e-a-1,  or 
p-a-l-e ;  and  this  difference  finds  expression  in  the 
constitutional  formulas*  of  the  substances.  These 
formulas  for  the  two  compounds  C2H4CI2,  are: 

H  H 

H   C-H  H    C-Cl 

H-C-Cl  ^^^^  H-C-Cl 

'  I  I 

CI  H 

Complexity  of  Organic  Molecules. — While  inor- 
organic  molecules  consist  of  only  a  few  atoms,  and 
are   therefore  very  simple   in   their   construction,  as: 

*  These  formulas  must  not  be  understood  to  represent  in  any  sense  the 
relative  positionx  of  the  atoms,  but  only  the  relations  which  they  bear  to  one 
another,  aa  shown  by  chemical  reactions. 


PARAFFINES    AND    THEIR    DERIVATIVES.      189 

H2O,  CO2  ;  organic  frequently  contain  a  large  number, 
and.  are  extremely  complex,  as:  Sugar  =  C,2H220||, 
having  45  atoms  in  a  molecule;  stearin  =  CsyHnoOg, 
having  173  atoms;  albumin=C72H|,oN,8S022,  having 
222  atoms,  and  perhaps  even  more. 


THE     PARAFFINES     AND     THEIR 
DERI  VATI  V  ES. 

Marsh-gas,  CH4  (page  71),  is  the  first  member  of 
a  series  of  hydrocarbons  whose  common  difference 
is  CH2,  and  whose  general  formula  may  be  written 
CnH2n+2-  ParafRue  {parum,  little;  affinis,  affinity), 
so  called  because  acids  and  bases  have  no  effect 
upon  it,  is  a  mixture  of  hydrocarbons  of  this  series, 
and  gives  it  its  name.  All  of  the  members  of  the 
paraffine  series  are  characterized  by  their  chemical 
indifference.  In  the  table  below  are  given  the  names 
and  formulas  of  the  lowest  members  of  the  series : 

Pi^RAFFlNE    HYDROCi^RBONS,   C„H2n.2- 

BOILING    POINT. 

Methane   (Marsh-gas) CH4.  Gas. 

Ethane    C2H6  Gas. 

Propane ....  C3H8  Gas. 

Butane    C4H10  1° 

Pentane C5H12  37° 

Hexane CgHi^.  7 '-5° 

Heptane C7  H  ,6  98° 

Octane CgH ,8  1 24° 

Nonane C9H20  150-8° 

Etc.  Etc. 


190  ORGANIC    CHEMISTRY. 

There  are  also  many  other  homologous  series  of  hy- 
drocarbons. All  the  hydrocarbons  in  the  foregoing  list, 
and  many  more  of  the  same  series,  occur  in  petroleum. 

Petroleum  {petra,  a  rock ;  oleum,  oil)  is  probably 
the  product  of  the  distillation  of  organic  matter  be- 
neath the  surface  of  the  earth.  It  is  not  alwaj's 
connected  with  coal,  as  it  is  often  found  outside  the 
coal-measures,  as  in  New  York  and  Canada.  The  dis- 
tillation must  have  taken  place  at  a  much  greater 
depth  than  that  at  which  the  oil  is  now  found,  as  it 
would  naturally  rise  through  the  fissures  of  the  rock 
and  gather  in  the  cavities  above.  Sometimes  the  oil 
has  collected  on  the  surface  of  subterranean  pools  of 
salt-water,  so  that  after  a  time  the  oil  is  exhausted, 
and  salt-water  only  is  pumped  up ;  or  if  the  well 
strikes  the  lower  part  of  the  cavity,  the  water  will 
first  be  pumped,  and  afterward  the  oil.  The  crude 
oil  from  the  well  is  purified  by  distillation,  and  treat- 
ment with  concentrated  H2SO4  and  alkalies.  By  the 
distillation  it  is  divided  into  several  parts  (each  a 
mixture  of  hydrocarbons),  which  are  called  cymo- 
gene,  rhigoline,  gasoline,  naphtha,  benzine,  kcrt)sene.* 


*  Kerosene  contains  CoHjo— CnHa,.  Kerosene  accidents  generally  rise 
from  the  presence  of  naphtha.  This  is  a  cheap,  light,  dangerous  oil.  Its 
vapor,  however,  is  not  explosive  unless  mixed  with  air.  While  a  lamp, 
which  contains  adulterated  kerosene,  is  burning  quietly,  there  is  no  danger. 
The  vapor  rises  from  the  oil,  fills  the  empty  space  in  the  lamp,  but  being 
unmixed  with  air,  can  not  explode.  Let,  however,  a  draught  of  cold  air 
strike  it,  or  carry  it  into  a  cold  room— instantly  the  vapor  will  be  condensed, 
the  air  will  rush  in,  and  a  dangerous  mixture  be  formed.  Or  when  the 
light  is  extinguished  at  night  the  vapor  will  cool,  air  pass  in,  and  a  mixture 
be  produced  which  will  be  ready  to  explode  when  the  lamp  is  relighted. 
Properly  purified,  kerosene  is  no  more  explosive  than  water,  and  will  even 
extinguish  a  flame  applied  to  it  at  the  ordinary  temperature.    Dr.  Nichols 


PARAFFINES    AND    THEIR    DERIVATIVES.       191 

The  portion  which  is  heavier  than  kerosene  and  boils 
at  a  higher  temperature,  yields  lubricating  oil  and 
paraffine. 

Paraffine  is  a  hard  white,  tasteless  solid,  melting 
at  44°  C.  It  is  used  for  making  candles.  It  was  dis- 
covered in  1830,  as  a  product  of  beech-wood,  but  all 
of  the  paraffine  of  commerce  is  now  obtained  from 
petroleum. 

Bitumen  or  Asphaltum  is  another  natural  product, 
consisting  chiefly  of  hydrocarbons.  It  is  found  in 
many  parts  of  the  world,  sometimes  pure,  sometimes 
associated  with  various  minerals.  On  the  island  of 
Trinidad  is  a  lake  of  bitumen  one  and  a  half  miles  in 
circumference.  Near  the  shore  it  is  hard  and  com- 
pact, except  in  hot  weather,  when  it  becomes  sticky. 
At  the  center  it  is  soft,  and  fresh  bitumen  boils 
up  to  the  surface.  Asphaltum  is  found  in  immense 
quantities  in  California  and  in  Canada.  The  bitu- 
men is  used  for  the  same  purposes  as  pitch,  which 
it  closely,  resembles.  It  is  a  natural  cement  for 
laying  stone  or  brick.  It  was  used  in  building  the 
walls  of  Babylon,  for  which  purpose  it  was  gathered 
from  the  fountain  of  Is,  on  the  banks  of  the 
Euphrates.  It  was  a  prominent  ingredient  in  the 
"Greek  Fire,"  so  much  used  by  the  nations  of  East- 
ern Europe  in  their  naval  wars,  even  as  late  as  the 
fourteenth    century.     This   consisted  of  bitumen,  sul- 

gives  the  following  simple  test :  Fill  a  bowl  partly  full  of  hot  watei'.  Insert  a 
thermometer,  and' add  cold  ivater  until  the  temperature  is  110°  F.  Then  jxmr  into  the 
Ixnvl  a  xpoonfid  of  kerosene,  and  apply  a  lighted  match.  If  it  takes  Jire,  the  oil  con- 
tains naphtha  and  is  dangerous.  See  also  an  article  in  Popular  Science  Monthly 
for  February,  1884. 


192  OKGANIC     CHEMISTRY 

phur,  and  pitch,  and  was  thrown  through  long,  copper 
tubes,  from  hideous  figures  erected  on  the  prow  of 
the  vessel.  Bitumen  is  used  in  making  pavements, 
as  in  Washington  and  Paris. 

Artificial  Preparation  of  the  Paraffines. — Methane, 
CH4,  may  be  made  by  leading  vapor  of  carbon  disul- 
phide,  CS2,  mixed  with  HgS,  over  heated  Cu  : 

CS2  +  2H2S  +  8Cu  =  CH4  +  -ACusS. 

This  reaction  is  very  interesting,  because  it  shows 
that  it  is  possible  to  make  this  organic  compound 
from  the  elements ;  for  CS2  is  prepared  by  the  action 
of  S  vapor  on  C  (page  110),  and  HgS  can  be  produced 
by  passing  H  through  boiling  S,  or  by  burning  S 
vapor  in  an  atmosphere  of  H. 

The  interest  in  this  reaction  becomes  still  greater 
when  we  learn  that  the  other  members  of  the  series 
can  be  made  from  CH4.  The  way  in  which  this  may 
be  done  is  the  following  :  1st.  One  atom  of  H  in  CH4. 
is  replaced  by  an  atom  of  CI,  by  the  action  of  CI  on 
CH4,  giving  the  compound  CH3CI.  2d.  Two  .molecules 
of  CH3CI  are  acted  upon  by  Na: 

2CH3CI  +  2Na=  2NaCl  +  CsHg. 

This  gives  the  second  member  of  the  series, 
ethane,  in  which  two  C  atoms  are  linked.  Then  by  a 
similar  process  the  higher  members  may  be  formed, 
thus  : 

CH3-CH2CI  +  CH3CI  4    iiNa=r2NaCl  +  CgHg; 

and  CH3-CH2-CH2CI  +  CH3CI  4  2Na  =  2NaCl  +  C^H.o, 
or,  2CH3-CH2CI  -f  2Na==2NaC]  +  C^Hjo. 


•  OXY'GEN     COMPOUNDS     OF     PARAFFINES.      193 

THE     OXYGEN     COMPOUNDS    OF 
THE     PARAFFINES. 

THE    ALCOHOLS. 

The  alcohols  are  compounds  which  may  be  re- 
garded as  hydrocarbons,  in  which  the  univalent 
group  OH,  called  hydroxy!,  has  replaced  H,  It  is  con- 
venient to  consider  the  alcohols  as  hydroxides  of 
certain  groups  of  radicals.  Thus  the  alcohol  derived 
from  methane,  CH3OH,  is  regarded  as  the  hydroxide 
of  the  radical  CH3,  which  is  called  methyl;  the 
alcohol  from  ethane,  C2H5OH,  as  the  hydroxide  of 
C2H5,  ethyl,  and  so  on ;  and  the  alcohols  themselves 
are  commonly  called  methyl  alcohol,  ethyl  alcohol 
etc.  These  organic  radicals  can  not  be  isolated.  They 
are  analogous  to  the  inorganic  group  or  radical  NH4 
(page  136),  and  the  analogy  of  the  alcohols  to  metal- 
lic hydroxides  is  readily  seen.  The  alcohols,  as  well 
as  the  other  derivatives  of  the  paraffines,  can  be 
artificially  prepared. 

Methyl  Alcohol,  CH3OH,  is  obtained  as  one  of  the 
products  of  the  destructive  distillation  of  wood.*  It 
is   a    light,   volatile    liquid,    which    closely   resembles 

*  When  hard  wood,  as  beech  or  oak,  is  heated  to  a  high  temperature, 
with  no  O  present,  or  an  imperfect  supply,  it  is  decomposed ;  the  charcoal 
remains,  while  a  large  number  of  products  is  formed,  among  which  are  H, 
CO,  COa,  H2O,  CH,,  methyl  alcohol,  acetic  or  pyroligneous  acid,  creosote, 
paraffin e,  tar,  etc. 

f'reoKote  (flesh-preserver)  is  a  colorless,  poisonous  liquid,  with  a  flavor  of 
burnt  wood.  It  has  powerful  antiseptic  properties.  It  imparts  to  smoke  a 
characteristic  odor,  renders  it  irritating  to  the  eyes,  and  also  gives  to  it  the 
power  which  it  possesses  of  curing  hams,  beef,  etc.  Much  of  that  which  is 
sold  as  creosote  is  carbolic  acid.    (See  page  233.) 


194  ORGANIC     CHEMISTRY. 

ordinary  alcohol  in  all  its  properties.  It  is  used  in 
the  manufacture  of  aniline  dyes,  in  making  var- 
nishes, and  in  spirit-lamps. 

Ethyl  Alcohol,  CH3— CHgOH,  ordinary  alcohol,  is  the 
best  known  and  most  important  of  the  alcohols.  It 
is  formed  by  the  fermentation  of  saccharine  sub- 
stances, and  prepared  by  distillation  of  the  solution 
thus  produced.  In  this  way  an  alcohol  of  about  93 
per  cent,  can  be  obtained.  In  order  to  get  "  absolute  " 
alcohol,  this  product  must  be  mixed  with  quick-lime, 
which  retains  the  water,  and  again  distilled.-  Pure 
alcohol  boils  at  78°  C,  and  has  recently  been  frozen 
at  a  temperature  of  —130.5°  C. 

When  it  is  exposed  to  the  air  the  spirit  evaporates, 
while  moisture  is  absorbed  from  the  atmosphere.*  It 
burns  without  smoke  and  with  great  heat,  owing  to 
the  abundance  of  H  and  deficiency  of  C,  and  is  there- 
fore of  much  value  in  the  arts.  It  is  also  of  incal- 
culable importance  as  a  solvent  of  many  substances 
— roots,  resins,  fragrant  oils,  etc. 

Effects  of  Alcohol. — When  pure  it  is  a  deadly 
poison.  When  diluted,  as  in  the  ordinary  liquors,  it 
is  stimulative  and  intoxicating.  Its  influence  is  on 
the  brain  and  nervous  system ; — deadening  the  nat- 
ural affections,  dulling  the  intellectual  operations  and 
moral  instincts ;  seeming  to  pervert  and  destroy  all 
that  is  pure  and  holy  in  man,  while  it  robs  him  of  his 
highest  attribute — reason.    (See  "Physiology,"  p.  150.) 


♦  The  chemist  diacovei's  this  wlien  lie  neglects  to  put  the  extinguisher 
on  his  alcohol  lamp,  and  finds  that  he  can  not  relight  it  without  moistening 
the  wick  with  fresh  alcohol. 


FERMENTATIOiSr.  195 


FERMENTATION. 

If  a  pure  solution  of  grape-sugar  be  exposed  to 
the  air  it  will  undergo  no  change ;  but  if  there  be 
added  a  httle  ferment,*  or  any  albuminous  substance 
(^.  e.,  one  containing  N),  in  a  decomposing  state,  it 
will  immediately  commence  breaking  up  into  new 
compounds.  The  fermentation  is  due  to  the  presence 
of  small  organized  bodies,  which  find  materials  for 
their  sustenance  in  the  solution,  and  in  their  growth 
overcome  the  equilibrium  of  the  chemical  forces, 
causing  the  large  molecules  to  drop  into  smaller 
ones.  There  are  different  kinds  of  ferments,  which 
cause  different  kinds  of  fermentation. 

1st.  Alcoholic  Fermentation. — In  this,  the  grape- 
sugar  is  resolved  into  alcohol  and  carbon  dioxide. 
The  former  remains  in  the  liquid,  while  the  latter 
escapes  in  little  bubbles  of  gas.  The  reaction  may  be 
represented  thus  :    CgHigOe  =  :2C2HgO  +  2CO2. 

2d.    Acetic    Fermentation. f — This    often    succeeds 

♦  "In  many  cases,  spontaneous  fermentation  sets  in  without  the  ap- 
parent addition  of  any  ferment :  thus  ^vine,  beer,  milk,  etc.,  when  allowed 
simply  to  stand  exposed  to  the  air,  become  sour,  or  otherwise  decompose. 
These  changes  are,  however,  not  effected  without  the  presence  of  vegetable 
or  animal  life,  and  are  true  fermentations ;  the  sporules,  or  seeds  of  these 
living  bodies,  always  float  about  in  the  air,  and  on  dropping  into  the  liquid 
begin  to  propagate  themselves,  and  in  the  act  of  growing  evolve  the  prod- 
ucts of  the  fermentation.  If  the  above  liquids  be  left  only  in  contact  with 
air  which  has  been  passed  through  a  red-hot  platinum  tube,  and  thus  the 
living  sporules  destroyed  ;  or  if  the  air  be  simply  filtered  by  passing  through 
cotton  wool,  and  the  sporules  prevented  from  coming  into  the  liquid,  it  is 
found  that  these  fermentable  liquids  may  be  preserved  for  any  length  of 
time  without  undergoing  the  slightest  change."— Roscoe. 

t  There  are  also  other  forms  of  fermentation,  as  the  lactic,  yielding 
lactic  acid— the  acid  of  sour  milk ;  butyric,  yielding  butyric  acid,  etc. 


196  ORGANIC     CHEMISTRY. 

the  first  immediately,  if  not  checked,  and  the  alcohol 
is  broken  up  into  acetic  acid  and  water  ;  thus,  C2HgO  + 
O2  (from  the  air)  =  C2H4O2  +  H2O. 

Yeast  is  the  ferment  which  causes  alcoholic  fer- 
mentation. It  consists  of  microscopic  plants  {Saccha- 
romyces  cerevisice),  which  increase  by  the  formation 
of  multitudes  of  tiny  cells  not  more  than  ^Vo  of  an 
inch  in  diameter.  In  the  brewing  of  beer  they  grow 
in  great  abundance,  making  common  brewer's  yeast.* 

Malt. — In  making  malt,  the  barley  is  thoroughly 
soaked  in  water,  and  then  spread  on  the  floor  of  a 
dark  room,  to  heat  and  sprout.  Here  a  curious 
change  ensues,  identical  with  that  which  takes  place 
in  every  planted  seed.  Each  one  contains  starch  and 
a  nitrogenous  substance  called  gluten.  The  tiny 
plant  not  being  able  to  support  itself  in  the  begin- 
ning, has  here  a  little  patrimony  with  which  to  start 
in  life  ;  but,  as  the  starch  is  insoluble  in  the  sap,  it 
must  first  be  changed  to  a  soluble  form.  We  see, 
therefore,  the  need  of  a  ferment ;  but  it  would  not 
answer  to  store  up  in  the  seed  an  active  ferment,  as 
that  might  cause  a  change  before  the  plant  was 
ready  to  grow,  and  thus  the  plant's  capital  be 
wasted.  The  gluten  acts,  therefore,  as  a  latent  fer- 
ment. As  soon  as  the  seed  is  planted  it  absorbs 
moisture  from  the  ground,  is  turned  into  diastase — 
an    active    ferment  f — the    starch    is    converted  into 

*  The  yeast-cakes  of  the  kitchen  are  formed  by  exposing  moistened  In- 
dian meal,  containing  a  ferment,  to  a  moderate  temperature,  until  the 
gluten  or  albunainous  matter  of  the  cake  has  undergone  this  alcoholic  fer- 
mentation.   They  are  then  laid  aside  for  use. 

t  "Malt  does  not  contain  more  than  sirs  of  its  weight  of  diastase;  one 


FERMENTATIOJSr,  197 

dextrin  and  sugar,  dissolved,  and  immediately  ap- 
plied to  the  uses  of  the  growing  plant.  This  change 
takes  place  in  the  malting-room.  The  barley  sprouts, 
and  a  part  of  its  starch  is  turned  to  sugar,  so  as  to 
give  it  a  sweetish  taste.  If  this  germination  were 
allowed  to  proceed,  the  little  barley  sprout  would  turn 
the  sugar  into  woody  fiber.  To  prevent  this,  the 
grain  is  heated  in  a  kiln  until  the  germ  is  destroyed. 
Barley  in  this  condition  is  called  mali,  and  is  then 
transported  to  the  breweries. 

Brewing  Beer. — The  malt  is  crushed  and  digested 
in  water,  to  convert  the  remaining  starch  into  dex- 
trin and  sugar.  Hops  and  yeast  are  added,  and 
fermentation  immediately  commences.  Bubbles  of 
gas  rise  to  the  top  with  a  low  hissing  sound,  yeast 
gathers  in  a  foamy  cream  that  comes  to  the  surface 
of  the  tub,  while  the  alcohol  gradually  accumulates 
in  the  liquid.  The  beer  is  now-  drawn  off  into  tight 
casks,  where  it  undergoes  a  second  fermentation  ; 
the  flavor  ripens,  and  the  CO  2  collecting,  gives  to  the 
liquor,  when  drawn,  its  sparkling,  foamy  appearance. 

Lager.  Beer  {Lagern,  to  lie)  is  so  called  because 
it  is  allowed  to  lie  for  months  in  a  cool  cellar,  where 
it  ripens  very  graduallj^  It  is  also  fermented  much 
more  slowly  and  perfectly  than  ale  or  porter. 

Wine  is  made  from  the  juice  of  the  grape.  The 
juice,  or  must,  as  it  is  called,  is  placed  in  vats,  in  the 
cellar,  where  the  low  temperature  produces  a  slow 
fermentation.    AVhen  all  the  sugar  is  converted  into 

part  of  this  substance  being  sufficient  to  change  2,000  parts  of  starcli  into 
dextrin  and  sugar."— Peesoz  aitd  Payen. 


198  OKGANIC     CHEMISTRY. 

alcohol  and  CO2,  a  dry  wine  remains ;  when  the  fer- 
mentation is  checked,  a  sweet  wine  is  the  result ;  and 
when  bottled  while  the  change  is  still  going  on,  a 
brisk,  effervescing  wine,  like  champagne,  is  formed. 
The  flavor  or  "  bouquet "  of  wine  is  due  to  the  slow 
formation  of  a  fragrant  and  aromatic  ether.*  (See 
p.  206).  The  tartaric  acid  of  the  grape  gradually 
separates  and  collects  on  the  sides  and  bottoms  of 
the  casks  in  an  incrustation — tartar,  an  impure  acid 
potassium  tartrate,  from  which  tartaric  acid  and 
cream  of  tartar  are  made. 

Alcohol  in  Beer,  Wine,  etc. — Alcohol  is  the  intoxi- 
cating principle  of  all  varieties  of  liquors,  ale,  beer, 
wine,  cider,  and  the  domestic  wines.  Ale  and  porter 
contain  from  6  to  8  per  cent,  of  alcohol ;  wine  varies 
from  7  per  cent,  in  the  light  claret  to  17  per  cent, 
in  the  strong  Port  and  Madeira ;  brandy  and  whiskey 
have  from  40  to  50  per  cent. 

Ardent  Spirits. — When  any  fermented  liquor  is 
distilled,  the  alcohol  passes  over,  together  with  water 
and  some  fragrant  substances  which  are  condensed. 
In  this  way  brandy  is  made  from  wine  ;  rum,  from 
fermented  molasses  or  cane-juice  ;  whiskey,  from  fer- 
mented (?orn,  rye,  or  potatoes ;  and  gin,  from 
fermented  barley  and  rye,  afterward  redistilled  with 
juniper-berries.  The  accompanying  cut  represents  an 
apparatus  used  for  this  distillation.  A  is  the  boiler, 
B  the  dome,  C  a  tube  passing  into  S,  the  condenser, 
where    it   is  twisted    into    a    spiral    form    called   the 

*  OSnanthic  ether,   a   liquid  with   a   powerful   odor,   which   causes  the 
peculiar  smell  of  grape-wine. 


FERMENTATION, 


199 


worm,  in  which  the  vapor  from  the  boiler  is  con- 
densed, and  drops  out  at  D.  (See  "Physics,"  page 
188.) 


Fig.  69. 


A  sm 


Amyl  Alcohol,  CsHnOH,  is  the  chief  constituent  of 
"fusel  oil,"  found  in  whiskey  distilled  from  pota- 
toes. It  is  often  present  in  common  alcohol,  giving 
a  slightly  unpleasant  odor  when  it  evaporates  from 
the  hand.  It  is  extremely  poisonous,  and  as  it  is 
often  contained  in  liquors,  must  greatly  increase 
their  destructive  and  intoxicating  properties. 

Besides  these  alcohols  which  have  been  described, 
and  others  which,  like  them,  contain  but  one  hy- 
droxy! group,  there  are  alcohols  which  have  two, 
three,  and  more  OH  groups.  Among  these  the  most 
important  one  is  glycerin^  C3H5(0H)3,  which  is  a  con- 
stituent of  fats,  and  will  be  treated  later  (page  206). 


200  ORGANIC     CHEMISTliy. 


THE    ALDEHYDES    AND    ACIDS. 

When  alcohols  are  oxidized  they  are  converted 
into  acids.  By  taking  proper  precautions,  inter- 
mediate products,  called  aldehydes  {alcohol  dehydro- 
genatum),  can  be  obtained  from  alcohols  like  those 
we  have  considered.  The  two  stages  of  the  oxidation 
are  shown  by  the  following  equations : 

CH3-CH2OH  +  0  =  H2O  +  CH3-COH. 
CH3-COH  +  0  =  CH3-COOH. 

The  group  —  C  =  O.H  is  characteristic  of  the  alde- 
hydes ;  the  group  — C=O.OH,  "the  carboxyl  group" 
of  the  organic  acids. 

Ethyl  Aldehyde,  CH3— COH,  is  a  colorless  liquid 
boiling  at  2 1  °  C.  It  is  readily  oxidized  to  acetic 
acid  or  reduced  to  ethyl  alcohol.  It  has  a  peculiar 
and  characteristic  odor,  which  may  be  obtained  by 
holding  a  red-hot  coil  of  Pt  wire  in  a  goblet  contain- 
ing a  few  drops  of  alcohol. 

Formic  Acid,  CH2O2  or  HC  =  O.OH,  occurs  in  red 
ants  (formica  rufa)  and  stinging  nettles,  and  can  be 
obtained  from  them  by  distillation  with  water.  It  is 
best  prepared  by  heating  oxalic  acid  with  glycerin.* 
It  is  a  fiery,  pungent  liquid,  which  blisters  the  skin. 
It  is  a  monobasic  acid  (page  112),  the  H  of  the  car- 
boxyl group  being  alone  replaceable  by  metals,  and 
yields  salts  called  formates,  e.  g.  H— C=O.OK,  potas- 
sium formate. 

•  It  can  also  be  made  by  the  oxidation  of  methyl  alcohol,  OH,OH. 


THE     ALDEHYDES     AND     ACIDS.  201 

Acetic    Acid,   C2H4O2,    or    CH3— C=O.OH    {acetum, 
vinegar),  forms  from   two   to   four  per  cent,  of  com- 
mon vinegar,  whence  its  name.    The  strongest  acetic 
acid  is  l^nown  as  the  glacial,  since  it  crystallizes  into 
an   ice-like   solid   at   17°C.    It  has  an 

Fig.  70. 

aromatic  taste  and  pungent  odor,  and, 
after  a  time,  blisters  the  skin. 

Preparation. — Vinegar  is  made  on  a 
large  scale  by  allowing  a  weak  alcohol 
to  trickle  slowly  through  a  cask  filled 
with  beech  shavings,  which  have  been 
soaked    in    vinegar.      As    the    alcohol 

Making  Vinegar.  .  .  ■^        i., 

passes  down,  it  is  oxidized,  and  after 
two  or  three  repetitions  of  the  process,  it  becomes 
entirely  converted  into  acetic  acid  *  (vinegar). 

Cider  Vinegar. — By  the  alcoholic  fermentation, 
sweet  cider  becomes  ^^old  cider.''  By  exposure  to  the 
air  the  alcohol  passes  on  to  the  second  stage,  and  the 
acetic  acid  formed  produces  the  sour  taste  of  the 
vinegar. 

Pgroligneous  Acid,  wood-vinegar  (see  p.  192,  note), 
is  crude  acetic  acid.  It  is  used  in  making  acetates, 
from  which  the  pure  acid  is  obtained  by  the  action 
of  a  stronger  acid,  as  H2SO4. 

Properties. — Acetic  acid  is  monobasic.  One  of  its 
most  important  salts  is  "  sugar  of  lead  "  (CH3— C  = 
0,0)2Pb   (see    p.    164).       Vinegars  of    commerce  are 

*  The  oxidation  of  alcohol  into  acetic  acid  is  due  to  a  microscopic  organ- 
ism (mycodei~ma  aceti),  which  is  called  "mother  of  vinegar."  It  conveys  O 
from  the  air  to  the  alcohol.  In  the  "quick-vinegar  process"  described,  the 
organism  is  deposited  on  the  shavings  from  the  vinegar  with  which  they 
are  soaked. 


202  ORGANIC     CHEMISTRY. 

often  sharpened  by  the  addition  of  HgSO^  and  pun- 
gent spices.* 

Its  sole  use  as  a  food  is  as  a  condiment.  It  allays 
thirst,  and  was  anciently  carried  by  the  Roman 
soldiers  in  a  little  flask  for  that  purpose.  Sugar 
added  to  vinegar  quickly  passes  to  the  second  stage 
of  fermentation,  and  increases  its  strength.  Indeed, 
vinegar  is  sometimes  made  entirely  from  sweetened 
water  and  tea-leaves,  which  act  as  a  ferment.  It  pre- 
vents the  decomposition  of  both  animal  and  vegeta- 
ble substances,  and  is  hence  used  for  preserving  them. 

Preserves  frequently  "  work,"  as  it  is  called,  and 
then  sour.  The  bubbles  of  gas  which  rise  to  the 
surface  indicate  the  alcoholic  fermentation.  If 
neglected,  this  soon  passes  to  the  acetic  stage.  It 
may  be  checked  by  scalding,  which  destroys  the  fer- 
ment. 

Of  the  other  acids  of  this  series  containing  one 
carboxyl  group,  the  only  ones  of  especial  interest 
are  Palmitic  acid  CisHgjCO.OH,  and  Stearic  acid 
C17H35CO.OH,  which,  in  combination  with  glycerin, 
form  the  common  solid  fats.  Another  related  acid, 
the  Oleic,  is  a  constituent  of  the  liquid  fats  (see 
p.  206).  The  so-called  "stearin"  candles  are  made 
of  a  mixture  of  palmitic  and  stearic  acids. 

♦  We  can  easily  detect  these  by  evaporating  a  half-gill  in  a  saucer, 
placed  over  hot  water.  As  it  boils  down,  add  a  little  sugar,  taking  care  not 
to  allow  it  to  burn.  If  the  liquid  turns  black,  it  is  proof  of  the  presence  of 
HjSO..  As  the  last  evaporates,  the  odor  of  cayenne  pepper,  etc.  (if  there 
be  any),  can  be  readily  distinguished.  In  England,  commercial  vinegar  is 
permitted  by  law  to  have  one  part  in  a  thousand  of  oil  of  vitriol,  as  this 
keeps  it  from  molding. 


THE     ALDEHYDES     AND     ACIDS.  203 

A  few  important  acids,  which  may  be  regarded  as 
derivatives  of  the  paraffine  series,  and  which  contain 
two  or  more  carboxyl  groups,  are  treated  below. 

Oxalic  Add,  C2H204.(C=0,0H)2,  is  familiar  in  the 
sour  taste  of  rhubarb,  sorrel,  etc.  In  these  plants 
the  acid  is  combined  with  K  and  Ca.  It  may  be  pre- 
pared by  the  action  of  HNO3  on  sugar.*  It  is  a 
potent  poison.  The  antidote  is  powdered  magnesia, 
or  chalk,  stirred  in  HgO.  It  is  a  test  of  lime,  forming 
a  delicate  white  precipitate  of  calcium  oxalate.  A 
solution  of  oxalic  acid  is  much  used  to  remove  ink 
stains,  and  is  often  sold  for  this  purpose  under  the 
deceptive  name  of  "  salts  of  lemon."  The  acid  unites 
with  the  Fe  of  the  ink,  and  the  iron  oxalate  thus 
made  is  soluble  in  HgO.  It  should  be  washed  out 
immediately,  as  it  will  corrode  the  cloth. 

CH(OH)CO.OH\ 
Malic   Acid    (C4H6O5,   1  I,   occurs  abun- 

CH2CO.OH       / 

dantly  in  most  acid  fruits,  particularly  in  unripe  ap- 
ples, whence  its  name  from  malum,  an  apple.  Citric 
acid,  C3H4(0H)  (C0.0H)3  {citrus,  a  lemon),  the  acid  of 
the  lemon,  lime,  etc.,  is  often  found  associated  with 
it,  as  in  the  gooseberry,  raspberry,  and  strawberry. 
Citric  acid  is  used  in  medicine  as  magnesium  citrate. 

CH(OH)  CO.OHX 
Tartaric   Acid   (CAHgOe,  1  I,   exists   in 

CH(OH)  CO.OH/' 


*  Oxalic  acid  is  made  on  a  large  scale  from  sawdust,  soda,  and  caustic 
potash.  The  woody  fiber  is  resolved  into  oxalic  acid,  which  combines  with 
the  bases,  forming  sodium  and  potassium  oxalates.  From  these  the  acid  is 
readily  obtained.  Sawdiist  will  yield  more  than  half  its  weight  of  crystals 
of  this  salt. 


204  ORGANIC     CHEMISTRY. 

many  fruits,  principally  in  the  grape,  combined  with 
K  as  acid  potassium  tartrate  ( "  bitartrate  of  potash  "). 
This  settles  during  the  fermentation  of  wine  (see  p. 
198),  and  when  purified  is  called  cream  of  tartar, 
from  which  the  acid  is  prepared.  It  forms  trans- 
parent crystals  of  a  pleasant  acid  taste,  which  are 
permanent  in  the  air.  Its  aqueous  solution  gradually 
becomes  moldy,  and  spoils.  Tartar  emetic  is  an 
antimony  potassium  tartrate.  Rochelle  salt  is  a  so- 
dium potassium  tartrate ;  it  is  commonly  used  in 
medicine  in  the  form  of  ScidJltz  poiudcrs.  These  are 
contained  in  a  blue  and  a  white  paper.  The  former 
holds  120  grains  of  Rochelle  salt,  and  40  grains  of 
bicarbonate  of  soda  ;  the  latter,  3  5  grains  of  tartaric 
acid.  They  are  dissolved  in  separate  goblets.  The 
one  containing  the  acid  is  emptied  into  the  other, 
when  the  COg  is  set  free,  producing  a  violent  effer- 
vescence, and  disguising  the  taste  of  the  medicine. 


THE     ETHERS     AND     ETHEREAL 
SALTS. 


^  The  ethers  are  oxides  of  the  organic  radicals. 
They  are  thus  analogous  to  the  metallic  oxides,  just 
as  the  alcohols  are  to  the  metallic  hydroxides,  and 
are  related  to  the  alcohols  in  the  same  way  that  KgO 
is  related  to  KOH.  Each  of  the  alcohols  has  its  cor- 
responding ether.    Thus  we   find  : 

Methyl  ether  (CHj),©,  coiTesponding  to  methyl  alcohol,  CH3OH. 
Ethyl  ether  (C...H5),0,  correspondiiiK  to  ethyl  akohol,  OJI.OH. 
Propyl  ether  (C3H,)jO,  correspoudiug  to  propyl  alcohol,  C3II7OII. 
Etc.,  etc. 


THE     ETHERS     AND     ETHEREAL     SALTS.       205 

Such  ethers  as  these,  in  which  two  radicals  of  the 
same  kind  are  united  with  0,  are  called  simple 
ethers.  It  is  easy  to  make  ethers  which  contain  dif- 
ferent radicals,  as,  for  instance,  CH3  — 0— C2H5;  and 
in  such  cases  they  are  called  mixed  ethers. 

Ethyl  Ether  (C2H5)20,  Common  or  ^^  Sulphuric^'' 
Ether^  is  made  by  heating  a  mixture  of  common 
alcohol  and  H2SO4.  It  is  a  colorless,  very  volatile 
liquid  of  a  peculiar  odor.  It  is  much  lighter  than 
water,  and  somewhat  soluble  in  it.  Ether  boils  at 
85°  C  Its  vapor  is  thirty-seven  times  heavier  than 
hydrogen,  and  can  be  poured  like  CO2.  It  is  very  in- 
flammable, and  its  vapor,  with  air,  forms  an  explosive 
mixture.!  Ether  is  a  valuable  ana3sthetic,  and  is  ex- 
tensively used  in  surgery. 

Ethereal  Salts  are  salts  in  which  an  organic  radi- 
cal occupies  the  place  of  the  metal  in  an  ordinary 
salt.    Thus,  in  making  ether  from  alcohol  by  the  ac- 

C  H 
tion    of    H2SO4,    there    is    first    formed      2    5  so 4,    in 

which  the  radical  C2H5  has  replaced  a  H  atom  of  the 
acid;  it  is  analogous  to  KHSO4,  which  is  formed  by 
the  action  of  H2SO4  on  KOH  : 

KOH  +  H2SO4  =  H2O  +  KHSO4. 
C2H5OH  +  H2S04=  H2O  +   (C2H5)HS04. 

As  other  examples  of  ethereal  salts,  or  compound 
ethers,  as  they  are  often  termed,  we  have:  Ethyl 
sulphate  (C2H5)2S04.  (analogous  to    K2SO4.) ;   ethyl   ni- 

*  This  name  was  given  to  it  because  HjSO,  is  used  in  its  manufacture, 
and  not  because  it  contains  any  S. 

t  Never  use  ether  in  the  neighborhood  of  flames. 


206  ORGANIC     CHEMISTRY. 

trate,  C2H5NO3  ;  ethyl  chloride,  C2H5CI ;  ethyl  acetate, 
CH3-CO.OC2H5. 

A  number  of  ethereal  salts  are  extensively  sold  as 
flavoring  extracts  for  the  use  of  confectioners  and 
cooks.  The  essence  of  jargonelle  pear  is  an  alcoholic 
solution  of  amyl  acetate  ;  apple  oil,  of  aniyl  valerian- 
ate ;   pine-apple,  of  ethyl  butyrate. 

To  this  same  class  of  compounds  belong  also  the 
natural  fats,  most  of  which  are  mixtures  of  the 
ethereal  salts  which  glycerin  forms  with  palmitic, 
stearic,  and  oleic  acids,  and  which  are  called  palmitin, 
stearin,  and  oletn.  Butter  consists  of  the  glycerin 
salts  of  seven  acids,  all  derivatives  of  the  paraffine 
series. 

The  Fats  and  Glycerin. — PalmMin  and  Stearin 
are  solids,  while  olein  js  liquid.  Therefore,  the  larger 
the  proportion  of  olein  which  a  fat  contains,  the 
lower  its  melting  point,  and  the  softer  it  is.  Fats 
especially  rich  in  palmitin  are  human  fat  and  palm 
oil ;  in  stearin,  mutton  tallow,  beef  tallow,  and  lard ; 
in  olein,  sperm-oil,  and  codliver  oil. 

Glycerin  is  an  alcohol  containing  three  OH  groups, 
C3H(0H)3,  and  its  ethereal  salts,  with  the  fatty  acids, 
are: 

(CsHaiCO.OaCaHs,  glycerin  tripalmiteite  or  palmitin, 
(CiiHasCO.OaCjIIs,  glycerin  tristearate  or  stearin, 
(C,8H3,CO.O)3C3H5,  glycerin   trioleate  or  ole'in. 

Glycerin  is  obtained  from  the  natural  fats  by  heat- 
ing them  with  lime  or  lead  oxide,  or  by  the  action  of 
superheated  steam.  In  the  former  cases,  the  calcium 
or  lead  salt  of  the  acid  is  formed,  and  the  glycerin 


THE     ETHERS     AND     ETHEREAL     SALTS.        207 

set  free ;  in  the  latter  case,  the  fat  is  decomposed  at 
once  into  acid  and  glycerin.  The  acids,  when  cool, 
are  subjected  to  great  pressure ;  the  oleic  flows  out, 
leaving  the  stearic  and  palmitic  acids  as  a  milk- 
white,  odorless,  tasteless  solid,  which  .  is  commonly 
called  stearin^  and  extensively  used  in  the  manufact- 
ure of  stearin  or  adamantine  candles* 

Glycerin  is  an  odorless,  transparent  syrup.  It  is 
soluble  in  H2O  and  alcohol.  On  account  of  its  heal- 
ing properties,  its  use  is  common  in  dressing  wounds, 
insect  bites,  chapped  hands,  etc. 

By  the  action  of  HNO3  and  H2SO4,  glycerin  is  con- 
verted into  nitro-glycerin  (C3H5(N03)3,  glycerin  ni- 
trate, a  compound  ether),  an  oil  that  often  explodes 
with  fearful  violence  by  a  slight  concussion.  Dynor- 
mite,  used  in  blasting,  is  powdered  silex,  or  infusorial 
earth  ("Geology,"  p.  48),  saturated  with  nitro-glycerin. 

Soap. — If  sweet-oil  and  H2O  be  placed  in  a  test- 
tube  and  shaken,  they  will  mix,  but  not  unite  ;  for 
on  standing,  the  oil  will  rise  to  the  top.  Add,  how- 
ever, caustic  potash  or  a  little  "lye"  (see  p.  129), 
when,    on    heating,    a    clear,    soapy   solution  will    be 

*  Wax  candles  are  manufactured  hy  the  following  process :  A  large  num- 
ber of  cotton  wicks  are  hung  upon  a  revolving  frame  with  projecting  arms. 
The  wicks  are  fitted  at  the  ends  with  metal  tags  to  keep  the  wax  from 
covering  that  part.  As  the  machine  slowly  turns,  a  man,  standing  ready 
with  a  vessel  of  melted  wax,  carefully  pours  a  little  upon  each  wick  in 
succession.  This  process  is  repeated  until  the  candles  reach  the  desired 
size.  They  are  then  rolled  on  a  smooth  stone  slab,  the  tops  cut  by  conical 
tubes,  and  the  bottoms  trimmed,  when  they  are  ready  for  use.  The  large 
tapers  burned  in  Catholic  cathedrals  are  made  by  placing  the  wick  on  a 
sheet  of  wax,  rolling  it  up  till  the  right  thickness  is  reached,  when  the 
candle  is  trimmed  and  iK)lished  as  before.  Spermaceti  candles  are  run  from 
the  white,  crystalline,  solid  fat  which  is  found  with  sperm-oil  in  the  head 
of  the  sperm-whale, 


208  ORGANIC     CHEMISTRY. 

formed.  The  K  of  the  alkali  has  combined  with  the 
oleic  and  palmitic  acids  of  the  oil,  making  two  new 
salts  —  potassium  oleate  and  potassium  palmitate ; 
while  the  expelled  glycerin  remains  floating  in  the 
liquid. 

The  manufacture  of  soap  is  based  on  this  princi- 
ple.* A  variation  in  the  alkaline  base  and  the  fat 
or  oil  used,  produces  the  different  kinds  of  soap. 
Potash,  on  account  of  its  affinity  for  H2O,  forms  soft- 
soap.  Soda  is  not  deliquescent,!  and  hence  makes 
hard^soap.X  Lard  forms  a  softer  soap  than  tallow. 
Castile  soap  is  made  from  olive-oil  and  soda.  Its 
mottled  appearance  is  due  to  the  coloring  matter 
which  is  stirred  through  it  while  it  is  yet  soft. 
Home-made  soap  is  prepared  by  boiling  "lye"  and 
"  grease."  §  As  the  latter  contains  such  a  variety  of 
fatty  substances,  the  soap  generally  consists  of  the 
three  salts — potassium  oleate,  palmitate,  and  stearate. 
Yellow  soap  contains  some  resin  in  place  of  fat. 
CoGoanut-oil  makes  a  soap  which  will  dissolve  in  salt 
water,  as  it  contains  an  excess  of  alkali.  Soap-balls 
are   made   by  dissolving  soap  in  a  very  little  water, 

*  Saponification  (sa]>o,  soap ;  facere,  to  make)  is  the  process  of  separating 
the  fatty  acids  and  glycerin,  and  is  so  named  even  when  no  soap  is  formed. 
One  method  is  as  follows :  Tallow  or  lard  is  boiled  with  lime,  and  thus 
made  into  a  calcium  soap.  This  is  decomposed  by  H5SO,,  forming  cal- 
cium sulphate,  which,  being  insoluble,  sinks  to  the  bottom,  leaving  the 
three  acids  of  the  fat  floating  upon  the  surface. 

+  A  deliquescent  substance  is  one  that  dis.solves  in  HjO,  which  it  ab- 
sorbs from  the  air. 

t  Soap  is  frequently  adulterated  with  gypsum,  lime,  pipe-clay,  or  sodium 
silicate.  These  may  be  detected  by  dissolving  a  piece  of  the  soap  in  dis- 
tilled water  or  alcohol,  and  noticing  if  there  be  any  precipitate. 

§  The  heat  hastens  the  chemical  change,  which  takes  place  more  slowly 
in  making  what  is  known  as  "cold  soap." 


HALOGEN    DERIVATIVES    OF    PARAFFINES.     209 

and  then  working  it  with  starch  to  a  proper  consist- 
ency to  be  shaped  into  balls.  White  toilet-soaps  are 
made  from  lard  and  soda.  The  curdling  of  soap  in 
hard  water  is  caused  by  the  formation  of  a  calcium 
or  a  magnesium  soap,  which  is  insoluble  in  HgO,  and 
floats  on  the  top  as  a  greasy  scum.* 

The  Cleansing  Qualities  of  Soap. — There  exudes 
constantly  from  the  pores  of  the  skin  an  oily  per- 
spiration, and  this,  catching  the  floating  dust,  dries 
into  a  film  which  will  not  dissolve  in  HgO.  The  alkali 
of  the  soap  combines  with  this  oily  substance,  and 
makes  a  soluble  soap.  In  addition,  the  alkali  also 
dissolves  the  cuticle  of  the  skin,  and  thus  produces 
the  "soapy  feeling,"  as  we  term  it,  when  we  handle 
soap. 

— «>•-» 

HALOGEN     DERIVATIVES    OF 
THE     PARAFFINES. 

The  halogens  can  be  caused  to  replace  one  or  more 
atoms  of  H  in  the  paraffines,  and  many  of  their  de- 
rivatives. A  few  only  of  the  compounds  thus  formed 
are  of  practical  importance. 

Chloroform,  CHCI3,  tri-chlor-metkane,  is  prepared 
by  distilling  alcohol,  C2H5OH,  with  chloride  of  lime. 
It  is  a  colorless,  heavi^  liquid  of  a  sweetish  taste  and 
ethereal  odor.  It  is  scarcely  soluble  in  water,  and 
when  shaken  with  it  quickly  settles  out  at  the  bot- 
tom.     It   should  evaporate   without   any   unpleasant 

*  A  soap  made  from  lard,  in  water  containing  calcium  carbonate,  would 
undergo  the  following  reaction :  Potassium  oleate  +  calcium  carbonate  = 
calcium  oleate  +  potassium  carbonate. 


210  ORGANIC     CHEMISTRY. 

odor  or  residue.  It  boils  at  62°  C.  It  is  very  useful 
as  an  anaesthetic,  and  is  employed  as  a  solvent  of  I, 
P,  S,  caoutchouc,  fatty  and  resinous  bodies. 

Iodoform,  CHI3,  made  by  bringing  together  so- 
dium carbonate,  alcohol  and  iodine,  is  a  solid.  It 
forms  small  yellow  crystals,  which  melt  at  119°  C. 
It  is  used  in  surgery. 

Chloral,  CCI3— CHO,  tri-chlor-aldehi/de,  is  formed 
by  passing  CI  through  absolute  alcohol.  It  is  an  oily 
liquid  which  combines  with  HjO,  making  Chloral 
Hydrate,  a  white,  crystalline  substance,  much  used 
to  induce  sleep.  Taken  in  proper  quantities,  it  is 
entirely  safe,  and  is  exceedingly  pleasant  in  its  in- 
fluence. 


THE      CARBOHYDRATES. 


STARCIf,   WOODY   FIBER,    AND    SUGp. 


Fig.  71. 


1.     STARCH      (CfiHioOg). 

Source. — Plants  accumulate  it,  1,  in  their  roots,  as 
the  carrot,  the  turnip,  etc.;  2,  in  subterranean  stems, 
as  the  potato,  of  which  it  forms  about  2  0  per  cent, ; 

3,  in  the  base  of  their 
leaves,  as  the  onion ;  4, 
in  the  seed,  as  corn,  of 
which  it  forms  about 
65  per  cent.,  the  bean, 
the  pea,  etc.  In  all 
these  it  is  stored,  up 
for  the  future  growth 
of  the  plant.  It  is  kept 
in  its  starch  form  (lest 
it  dissolve  in  the  first 
rain),  and  then  turned 
to  sugar  only  when  the 
plant  needs  it  in  growing.  (See  p.  196.)  Under  the 
microscope,  each  vegetable  is  found  to  have  its  pecu- 
liar form  of  starch  granule,  so  that  in  this  way  any 
adulteration  is  easily  detected.* 


I'utak)  Starch. 


*  "The  structure  of  the  grains  of  starch  is  very  beautifully  displayed  by 
placing  some  of  them  in  contact  with  a  drop  of  concentrated  solution  of 
zinc  chloride  (tinged  with  a  little  free  iodine)  on  the  field  of  the  micro- 


212 


ORGANIC     CHEMISTRY, 


Wheai  Starcli. 


Preparation. — Starch  is  made  from  wheat,  corn,  po- 
tatoes, etc.    The  process 

.  ,  .  Fio.  72. 

IS  essentially  the  same  m 
all.  The  potato,  for  ex- 
ample, is  ground  to  a 
pulp,  and  then  washed 
with  cold  water.  The 
starch  settles  from  this 
milky  mass  as  a  fine, 
white  precipitate. 

Properties. — Starch  is 
insoluble  in  cold  water  ; 
in  hot,  it  absorbs  HgO, 
swells,  and  the  granules 
burst,  forming  a  jelly-like  liquid,  used  for  starching. 
The  swelling  of  rice,  beans,  etc., 
when  cooked,  is  owing  to  this 
property.  By  heating  to  400° 
when  dry,  starch  undergoes  a 
peculiar  change  into  a  substance 
known  as  dextrin,*  used  as  a 
mucilage  on  envelopes  and  adhe- 
sive stamps,  for  making  "  fig- 
paste,"  and  stiffening  chintzes.  The  test  of  starch  is 
I,  which  forms  in  solution  the  blue  iodide  of  starch. 

scope.  No  change  takes  place  in  the  granules  until  a  little  water  is  added. 
They  then  become  of  a  deep  blue  color,  and  gradually  expand ;  at  first,  a 
frill-like  plaited  margin  is  developed  around  the  globules ;  by  degrees  this 
opens  out ;  the  plaits  upon  the  globule  may  then  be  seen  slowly  unfolding, 
and  may  be  traced  in  many  cases  into  the  wrinkles  of  the  frill ;  ultimately 
the  granules  swell  up  to  twenty  or  thirty  times  their  original  bulk,  and 
present  the  appearance  of  a  flaccid  sac."— Busk. 

♦  Dextrin  is  isomeric  with  starch,  but  is  not  discolored  by  I. 


Fig.  73. 


Bunting  of  Starch  Granule. 


CELLULOSE.  213 

Sago  is  the  starch  from  the  pith  of  the  palm-tree ; 
tapioca  and  arrow-root  are  made  from  the  roots  of 
South  American  marshy  plants.* 

Gum  is  found  in  the  juices  of  nearly  all  plants, 
and  frequently  exudes,  as  in  the  peach,  plum,  and 
cherry.  It  is  soluble  in  water,  but  not  in  alcohol. 
Gum  arabic,  which  flows  in  transparent  tears  from 
an  acacia  tree,  is  the  purest  form.f  Mucilage,  which 
occurs  in  gum  tragacanth,  linseed,  quince-seed,  etc., 
is  a  modification  of  gum,  and  is  insoluble  in  H2O.  It 
forms  with  it,  however,  a  gelatinous  liquid,  which  is 
exceedingly  useful. 

Vegetable  Jelly. — "A  variety  of  gum  called  pec- 
tose  exists  in  nearly  all  fruits  and  vegetables.  It 
gives  to  them  their  hardness  while  green." — Fremy. 
In  the  process  of  ripening,  or  by  heat,  acids,  etc.,  it 
is  turned -into  pectin.  We  find  this  abundant  in  the 
thick  juice  which  exudes  from  an  apple  while  baking. 
In  the  making  of  jellies,  pectose  is  converted  into  a 
mixture  of  pectosic  and  pectic  acids. 


2.     CELLULOSE     (CgHioOg). 

Sources. — If  a  thin  slice  of  wood  be  examined 
under  the  microscope,  it  will  be  seen  to  consist  of  a 
fibrous    substance    incrusted    and    compacted    with 


*  Very  many  of  the  farinaceous  preparations  sold  for  the  sick  and  in- 
valid, under  high-sounding  names,  are  simply  wheat  or  com  starch. 

t  It  is  a  soluble  salt,  being  composed  of  arabic  acid  (CisHaoOn,  Gelis), 
combined  with  K  and  Ca. 


214  ORGANIC     CHEMISTRY. 

woody  matter.  The  former  is  called  cellulin 
(CgHioOg).*  It  composes  the  cells  of  all  plants,  giving 
them  strength  and  firmness,  and  is  found  even  in 
delicate  fruits,  holding  their  luscious  juices.  It  occurs 
in  various  modifications,  in  wood,  nut-shells,  and 
fruit-stones.  In  the  heart  of  a  tree,  its  cells  are  hard 
and  dense ;  in  the  outer  part,  they  are  soft  and 
porous ;  in  elder-pith  and  cork,  light  and  spongy ;  in 
flax  and  cotton,  long,  pliable,  and  fibrous ;  in  the  bran 
of  wheat  and  corn,  digestible. 

Secretion. — All  vegetation  consists  of  these  simple 
cells.  They  seem  alike  to  the  eye,  yet  they  have  a 
very  diverse  power  of  secretion.  The  cell  of  the 
sugar-maple  converts  its  sap  into  sugar;  the  milk- 
weed, into  a  milky  juice;  the  caoutchouc,  intcj  rubber; 
the  rhubarb-plant,  into  oxalic  acid  ;  and  the  rose- 
petal,  into  the  most  delicate  of  perfumes. 

Cells  are  always  true  to  themselves.  There  seems 
to  be  a  law  of  God  stamped  on  each  one,  so  that 
when  we  cut  a  tiny  bud  from  one  tree  and  graft,  it 
into  another,  it  remains  consistent  with  itself.  It  de- 
velops into  a  limb,  and  years  pass  by.  The  few  single 
cells  become  a  myriad,  yet  they  have  not  changed. 
The  sap  flows  upward  in  the  tree ;  but  at  a  certain 
point — a  hidden  threshold  which  no  human  eye  can 
discern — it  comes  under  a  new  and  strange  influence. 
Here  it  is  transformed,  and  produces  fruit  and  flowers, 
in  accordance  with  another  and  different  growth. 
Somehow,   quince-juice    is    made    into    pears,   locust- 

*  It  is  probable  that  the  molecule  of  woody  fiber  is  some  multiple  of 
tliis  formula,  as  CnHaoOu. 


CELLULOSE.  215 

juice  blooms  out  into  fragrant  acacias,  and  sweet  and 
sour  apples  hang  upon  the  same  limb. 

Uses.  —  These  are  wonderfully  various.  Woody 
fiber  is  woven  into  cloth,  built  into  houses,  twisted 
into  rope,  twine,  and  thread,  made  into  paper, 
cut  into  fuel,  carved  into  furniture.  We  eat  it, 
wear  it,  walk  on  it,  write  on  it,  sit  on  it,  print  on 
it,  pack  our  clothes  in  it,  sleep  in  it,  ride  in  it,  and 
burn  it. 

Paper  is  made  from  cotton,  linen,  straw,  or  any 
substance  containing  cellular  tissue.  The  finest 
writing-paper  is  manufactured  from  linen  rags. 
These  are  first  "  shredded  "  upon  scythe-blades — i.  e., 
the  seams  are  ripped  open,  buttons  cut  off,  and  the 
dust  shaken  out.  2d.  They  are  steamed  in  a  solution 
of  chloride  of  lime  for  ten  or  twelve  hours,  until  they 
are  thoroughly  bleached.  3d.  They  are  received  by  a 
machine  that  alternately  lacerates  them  by  a  cylin- 
der set  with  razor-like  blades,  and  washes  them  with 
pure,  cold  water  for  six  hours,  until  they  are  reduced 
to  a  mass  resembling  rice  and  milk.  4th.  This  pulp 
receives  a  delicate  blue  tint  from  smalt*  5th.  It  is 
diluted  with  H2O  nearly  to  the  consistency  of  milk, 
and  strained  to  remove  the  waxed  ends  and  knots  of 
thread  that  cause  the  little  lumps  which  catch  our 
pen  when  we  write  rapidly  on  poor  pajjer.  6th.  It 
flows  over  an  endless  belt  of  wire-gauze,  about  thirty 
feet  in  length,  through  which  the  water  steadily 
drips  from  the  pulp,  as  it  slowly  passes  along,  gain- 
ing consistency  and   firmness.     7th.    It  comes   to   a 

*  Powdered  glass  colored  with,  oxide  of  cobalt. 


216  ORGANIC     CHEMISTRY. 

part  of  the  belt  called  the  "  dandy-roll,"  consisting  of 
a  cylinder,  on  the  surface  of  which  are  wires  arranged 
in  parallel  rows,  or  fancy  letters,  which  print  upon 
the  moist  paper  a  design  —  constituting  what  is 
termed  "  laid,"  or  "  wire-woven,"  paper.  8th.  The 
paper,  very  soft  and  moist  as  yet,  passes  between 
rollers  that  squeeze  out  the  water ;  then  between 
others  which  are  hot,  and  dry  it.  9  th.  It  comes  to  a 
vat  of  sizing,  composed  of  glue  and  alum,  into  which 
it  plunges,  and  at  the  opposite  side  emerges  only  to 
go  between  other  rollers,  that  press  and  dry  it,  at  the 
end  of  which  it  passes  under  a  cylinder  set  with 
knives,  that  clip  the  roll  into  sheets  of  any  desired 
size. 

Paper  Parchment  is  prepared  by  plunging  unsized 
paper  for  a  few  seconds  in  H2SO4,  of  a  specified 
strength,  then  washing  off  the  acid.  This,  in  some 
unknown  way,  changes  its  appearance  and  character, 
so  that  it  resembles  parchment,  while  its  toughness 
is  five  times  that  of  the  paper  from  which  it  was 
made. 

Linen  is  made  from  the  inner  bark  of  flax.  The 
plant  is  first  pulled  from  the  ground,  to  preserve  the 
entire  length  of  the  stalk;  next  "rotted,"  by  exposure 
to  air  and  moisture,  when  the  decayed  outer  bark  is 
removed  by  "breaking";  then,  by  " hatcheling,"  the 
long,  fine  fibers  are  divided  into  shreds,  and  laid 
parallel,  while  the  tangled  ones  are  separated  as 
"tow."  It  is  then  bleached  on  the  grass,  which 
renders  the  gray  coloring-matter  soluble  by  boiling 
in  lye.-    The  whitened  flax  is  lastly  woven  into  cloth. 


SUGAR.  217 

Cotton  consists  of  the  beautiful  hollow,  white  hairs 
arranged  around  the  seed  of  the  cotton-plant.  As 
it  is  always  pure  and  white — except  Nankin  cotton, 
which  is  yellow — it  would  require  no  bleaching  did 
it  not  become  soiled  in  the  process  of  spinning,  etc. 

Gun-Cotton. — Pyroxylin  {pur,  fire,  and  xulon,  wood) 
is  prepared  by  dipping  cellular  tissue — cotton,  saw- 
dust, printing-paper,  etc. — in  a  mixture  of  HNO3  and 
H2SO4  of  a  certain  specific  gravity.  It  is  then  care- 
fully washed  and  dried.  It  is  not  materially  changed 
in  appearance,  but  a  part  of  its  H  has  been  replaced 
by  NO2,  and  it  has  become  very  inflammable.  It 
burns  very  rapidly,  and,  unlike  gunpowder,  leaves  no 
residue.  It  explodes  on  percussion  with  a  force  which 
is  far  greater  than  that  of  gunpowder.  A  mixture 
of  gun-cotton  and  camphor  is  widely  used  under  the 
name  of  celluloid. 

Collodion  is  a  solution  of  gun-cotton  in  ether  and 
alcohol.  It  forms  a  syrupy  liquid,  which  is  much 
used  by  photographers. 


3.    SUGAR. 

Cane-Sugar  (C,2H220|  ,),*  Sucrose,  is  obtained  from 
the  sap  of  the  sugar-maple,  and  the  juice  of  the 
sugar-cane,  sorghum,  and  beet.     In  making  it  from 

*  A  very  brilliant  experiment  showing  the  presence  of  C  in  C12H32O1, 
is  obtained  by  putting  on  a  clean,  white  plate,  a  mixture  of  finely-pulver- 
ized white  sugar  and  KCIO3.  Upon  adding  a  few  drops  of  HoSO,,  a  vivid 
combustion  will  ensue.  By  mixing  with  the  sugar  a  few  iron  and  steel 
filings,  and  performing  the  experiment  in  a  dark  room,  or  out-of-doors  at 
night,  fiery  rosettes  will  flash  through  a  rose-colored  flame,  and  produce  a 
fine  effect. 


218  ORGANIC     CHEMISTRY. 

the  sugar-cane,  the  canes  are  crushed  between  iron 
cyhnders,  to  express  the  juice.  A  Httle  Ume  is  added 
to  neutralize  the  acids,  which  would  prevent  com- 
plete crystallization  of  the  sugar,  and  to  remove 
certain  substances  which  would  cause  fermentation, 
and  it  is  then  evaporated  to  a  thick  jelly,  and  set 
aside  to  cool.  The  sugar  crystallizes  readily,  forming 
brown  sugar,  which  is  put  in  perforated  casks  to  drain. 
The  drainings,  or  "mother-liquor,"  constitute  molasses. 

Refining. — Brown  sugar  is  dissolved  in  HgO,  filtered 
through  twilled  cotton  to  remove  the  coarse  impuri- 
ties, and  then  through  a  deep  layer  of  animal  char- 
coal. The  colorless  solution  is  next  evaporated  in 
vacuum  pans,  from  which  the  air  is  exhausted,  so 
that  the  sugar  boils  at  so  low  a  temperature  as  to 
avoid  all  danger  of  burning.  When  sufficiently  con- 
centrated, the  liquid  is  removed  and  set  aside  to 
crystallize.  If  the  mass  of  crystals  is  dried  in 
molds,  it  forms  loaf-sugar;  if  in  centrifugal  ma- 
chines, granulated  sugar*  The  drainings  constitute 
"  syrup,"  "  sugar-house  molasses,"  etc. 

Confectionery. — Terra  alba  (white  earth)  is  im- 
ported from  Ireland  for  use  in  lozenges,  drops,  etc.f 

*  This  apparatus  consists  of  a  cylindrical  drum  mounted  upon  a  vertical 
axis,  to  which  a  rapid  rotary  movement  can  be  given.  The  oiiter  side  of 
this  drum  is  made  of  a  stout  but  closely-woven  net-work.  The  drum  is 
inclosed  in  a  largo,  fixed,  cylindrical  vessel,  capable  of  holding  the  liquid 
which  may  pass  out  through  the  net-work.  A  charge  of  sugar  is  placed  in 
the  inner  drum,  which  is  then  made  to  revolve  I'apidly.  The  syrup  escapes 
through  the  wire-gauze  into  the  outer  drum,  while  the  crystals  are  rapidly 
dried. 

t  We  can,  and  should,  test  all  the  candy  we  purchase  by  putting  a  small 
piece  in  a  glass  of  water.  Wliatever  settles  to  the  Iwttom  and  remains  un- 
dissolved is  an  adulteration. 


SUGAR.  219 

Confectionery  is  often  colored  by  dangerous  poisons, 
so  that  prudence  forbids  the  use  of  any  colored 
candy.  Licorice  drops  are  frequently  only  the  poor- 
est brown  sugar,  terra  alba,  and  a  flavoring  of  licorice 
to  make  the  unwholesome  mixture  palatable.  Gum- 
drops  are  made,  not  from  gum  arable,  but  generally 
of  a  species  of  glue  manufactured  out  of  hoofs, 
parings  of  hides,  etc.  However  repugnant  it  may 
appear,  this  substance  is  perfectly  clean  and  whole- 
some. Rock  candy  is  formed  by  suspending  threads 
in  a  strong  solution  of  sugar.  It  crystallizes  upon 
the  rough  surface  in  large,  six-sided  prisms. 

Caramel,  familiarly  called  burnt  sugar,  is  formed 
whenever  sugar  is  heated  above  its  melting  point, 
as  when  sweetmeats  boil  over  on  the  stove ;  H2O  is 
lost,  and  C  remains  in  excess.  It  is  used  by  confec- 
tioners and  for  coloring  liquors. 

Grape -Sugar  (CgHigOg),  Dextrose,  is  found  in 
honey,  figs,  and  many  kinds  of  fruit.  Its  sweeten- 
ing power  is  about  three  fifths  that  of  cane-sugar. 

Sugar  from  Starch. — The  difference  in  the  con- 
stitution of  starch  and  grape-sugar  is  only  HgO.  By 
boiling  corn  or  potato-starch  with  dilute  H2SO4,  it  is 
transformed  into  dextrose.  The  solution,  evaporated 
to  a  syrup,  is  known  commercially  as  "  glucose," 
"mixing  syrup,"  etc.  When  evaporated  to  dryness, 
the  product  is  known  as  "grape-sugar."* 

*  Saw-dust,  paper,  and  even  rags,  can  in  the  same  way  be  converted 
into  sugar.  Indeed,  Professor  Pepper  speaks  of  seeing  some  made  out  of  an 
old  shirt.  Wonderful  beyond  our  comprehension  is  that  chemical  force 
which  can  transform  a  cast-off  garment  into  a  substance  which  will  delight 
the  palate.     (The  transformation  of  rags  into  paper  is  not  a  chemical  one.) 


220  ORGANIC     CHEMISTRY. 

"  Candied  Jellies,  Preserves,  Etc/' — The  sugar  of 
many  kinds  of  ripe  fruits  consists-  of  grape  or  cane 
sugar,  mixed  with  fruit-sugar.  The  latter  changes 
gradually  into  grape-sugar  and  crystallizes,  as  in 
honey,  dried  figs,  etc.* 


Necessity  of  Organization. — We  have  found  many 
elements  which  are  necessary  to  the  growth  of  our 
bodies,  but  still  we  can  not  live  upon  them.  We  need 
phosphorus,  but  we  can  not  eat  it,  for  it  is  a  deadly 
poison.  We  need  Fe,  but  it  would  make  a  most  un- 
savory diet.  We  need  CaO,  but  it  would  corrode  our 
flesh.  We  need  H,  but  it  must  be  combined  with  0, 
as  in  H2O,  to  be  of  any  value  to  us.  We  need  C,  but 
charcoal  would  form  a  very  indigestible  food.  If  we 
were  shut  up  in  a  room  with  all  the  elements  of 
nature,  we  not  only  could  not  combine  them  so  as 
to  produce  those  organic  substances  necessary  to  our 
life  and  comfort,  but  we  should  actually  die  of  starva- 
tion. We  thus  find  that  the  mineral  matter  must  be 
organized  before  we  can  use  it  to  advantage. 

Plants  Organize  Matter. — We  have  seen  that  in 
the  plant  the  sunbeam  decomposes  CO2,  and  returns 
to  the  air  the  life-giving  0 ;  that  we  can  not  create 
energy   ourselves,    or   draw   it   direct   from   the   sun, 

Thus  the  chemist  faintly  imitates  nature,  which,  ever  out  of  waste  and 
refuse,  springs  afresh.  The  fair  petals  of  the  lily  rest  upon  the  black  mud 
of  the  swamp,  and  the  pi"oducts  of  decay  come  back  to  us  in  objects  of  use 
and  forms  of  beauty. 

*  Fruit-sugar  is  isomeric  with  grape-sugar,  but  is  much  sweeter.  Tho 
latter,  as  it  is  noted  for  its  right-handed  rotation  of  tho  plane  of  jwlarized 
light,  is  called  dextrose  (ctextra,  right),  and  the  former,  from  its  left-handed 
rotation,  Isevulose  {l(ems,  left).    (See  "Physics,"  p,  J70,) 


THE     AROMATIC     COMPOUNDS.  221 

but  must  take  that  which  the  plant  has  hoarded 
for  us.  We  shall  now  find  that,  in  addition,  the  plant 
changes  inorganic  matter  to  organic.  It  takes  up  the 
elements  we  need  for  our  growth  and  for  use  in  the 
arts,  and  combines  them  into  plant-products,  such  as 
wood,  starch,  sugar,  etc.  We  are  thus  dependent 
upon  the  vegetable  world  for  the  grand  staples  of 
commerce  and  of  luxury — all  that  M^e  eat,  drink  or 
wear.  Each  tiny  leaf,  every  tree  and  shrub,  every 
spire  of  grass  even,  is  working  constantly  for  us.  The 
earth  was  once  a  burnt  body — the  cinders  of  the  vast 
fire  amid  which  it  had  its  origin,  (See  "Geology," 
p.  17.)  Every  organized  substance  now  on  its  sur- 
face has  been  rescued  from  the  grasp  of  0  by  the 
plants. 


THE     AROMATIC     COMPOUNDS. 

The  name  of  this  large  and  important  group  of 
compounds  is  due  to  the  fact  that  many  of  its  mem- 
bers occur  in  balsams,  resins  and  essential  oils  which 
have  an  aromatic  odor.  The  simplest  aromatic  hydro- 
carbon is  benzol,  or  benzene,  CgHg,  and  the  other 
hydrocarbons  and  compounds  of  the  group  are  de- 
rivatives of  this,  formed  by  the  replacement  of  its  H 
by  elements  or  groups. 

Benzene,  CgHg,  is  a  product  of  the  distillation  of 
coal-tar,  obtained  in  gas-making  (see  p.  72).  It  is  a 
colorless  oil,  which  is  a  good  solvent  for  gutta- 
percha,   caoutchouc,    and    fats.      It    is   lighter   than 


222  ORGANIC     CHEMISTRY. 

water,  boils  at  80.5°  C,  and  is  chiefly  used  for  the 
preparation  of  its  derivatives,  many  of  which  are  of 
the  greatest  importance. 

Nitre-Benzene,  CgHgNOg,  is  made  by  the  action  of 
nitric  acid  on  benzene.  It  is  a  heavy,  oily  liquid, 
with  an  odor  like  that  of  bitter  almonds.  It  is  some- 
times called  essence  of  mirbane,  and  is  used  in 
scenting  soap  and  in  perfumery,  but  is  chiefly  valu- 
able as  the  source  of  aniline,  from  which  are  prepared 
the  celebrated  coal-tar  dyes. — Example:  Mauve,  ma- 
genta, etc.  Who  but  a  chemist  would  have  searched 
in  black,  sticky  coal-tar  for  these  rainbow-tints,  the 
stored-up  sunshine  of  the  carboniferous  age ! 

Aniline,  CgHgNHa,  is  formed  by  the  action  of 
nascent  H  on  nitro-benzene.  On  a  large  scale,  it  is 
made  by  mixing  the  nitro-benzene  with  iron  filings 
and  HCl.  It  is  a  colorless  liquid,  which  becomes 
rapidly  colored  on  exposure  to  the  air.  It  is  a  strong 
base,  uniting  with  nearly  all  acids  to  form  crystal- 
line salts.  In  this  characteristic  it  resembles  ammo- 
nia, NH3,  and  it  may  be  looked  upon  as  ammonia  in 
which  an  H  atom  has  been  replaced  by  the  organic 
radical  phenyl^  CgHg.  By  treatment  with  oxidizing 
agents,  aniline  yields  a  great  variety  of  derivatives, 
among  them  the  exceedingly  valuable  aniline  dyes.* 

*  "In  1856,  Mr.  Perkin,  while  experimenting  ■with  aniline  in  hopes  of 
making  quinine,  treated  it  with  potassium  bichromate.  lie  did  not  suc- 
ceed in  his  attempt,  but  he  obtained  a  beautiful  purple  dye,  which  was  soon 
introduced  to  commerce  under  the  name  of  mauve.  A  host  of  imitators  at 
once  sought  to  c)btain  the  color  without  using  potassium  bichromate.  As 
the  only  use  of  the  latter  was  to  oxidize  tlie  aniline,  they  reasoned  that 
they  might  use  any  other  oxidizing  agent.  Arsenic,  among  other  substances, 
was  tried,  but,  instead  of  a  purple,  the  red  known  as  magenta  was  the  result. 


THE     AROMATIC     COMPOUNDS.  223 

Aniline  was  discovered  in  1826,  among  the  products 
of   the   dry   distillation   of   indigo,    and    received    its 
name  from  anil,  the  Portuguese  term  for  indigo. 
Phenol,    CgHjOH,   Carbolic  Acid*  is  noted   for  its 


The  coloring  matter,  however,  does  not  contain  any  arsenic ;  being  a  salt 
of  a  base  called  rosaniline.  Rosaniline  itself  is  colorless,  and  reveals  its 
magnificent  tints  only  in  its  compounds.  'The  crystals  of  its  salts  exhibit 
by  reflected  hght  the  metallic  green  color  of  beetles'  wings,  but  are  of  a 
deep  red  color  when  seen  by  transmitted  light.'  Magenta  is  manufactured 
on  an  enormous  scale  in  England,  more  as  a  substance  from  which  to 
obtain  other  dyes  than  for  direct  use  in  dyeing.  A  single  firm  produces 
twelve  tons  a  week.  The  quantity  of  magenta  furnished  by  one  hundred 
pounds  of  coal  is  very  small ;  but  this  is  compensated  for  by  its  intense 
coloring  power,  since  it  will  dye  a  quantity  of  wool  nearly  equal  in  weight 
to  the  coal.  In  making  magenta  on  the  large  scale,  there  are  considerable 
quantities  of  residual  products.  These,  of  course,  have  been  examined  with 
a  view  to  further  profit,  and  the  result  has  been  the  discovery  of  a  beauti- 
ful orange  color  called  phogp/iine.  This  is  much  used  to  produce  scarlet,  by 
first  dyeing  the  silk  or  wool  with  magenta,  and  then  passing  it  through  a 
bath  of  phosphine.  By  treating  magenta  with  aniline,  a  beautiful  blue  is 
obtained.  This  is  insoluble  in  water,  but  is  rendered  soluble  exactly  as  in- 
digo is,  by  treating  it  with  sulphuric  acid.  Another  curious  dye  formed 
from  aniline  is  known  as  Nicholsoji's  blue.  This  is  completely  discolorized  by 
alkalies,  and  the  color  is  restored  by  acids.  In  dyeing  with  it,  the  silk  or 
wool  is  first  immersed  in  a  colorless  solution  of  the  dye,  and  then  dipped 
into  dilute  sulphuric  acid,  when  the  blue  is  at  once  developed.  If  magenta 
is  heated  with  iodide  of  ethyl  or  methyl,  an  excess  of  the  iodide  being  em- 
ployed, a  most  beautiful  green  is  the  result.  If,  however,  this  green  is 
heated  sufficiently  to  drive  off  the  excess  of  iodide,  a  vaolet  color  is  the 
result ;  so  that  it  will  not  do  for  ladies  wearing  dresses  dyed  with  this 
green  to  sit  too  near  the  fire.  After  all  the  coloring  matter  has  been  ex- 
tracted from  the  aniline,  a  residue  remains  which  has  an  intense  black 
color,  and  is  largely  used  for  making  printing-ink.  Very  few  of  the  aniUne 
colors,  when  in  powder,  give  a  person  any  idea  of  the  color  which  they  will 
produce  when  moistened.  Magenta,  for  instance,  when  dry,  is  a  beautiful 
green,  with  a  bronze-like  luster.  It  is  a  pretty  experiment  to  coat  a  sheet 
of  glass  with  one  of  these  colors,  which  is  readily  done  by  dissolving  in 
alcohol  (Hofmann's  violet  being  the  best),  and  allowing  a  film  of  it  to 
evaporate  on  the  glass.  When  seen  by  transmitted  light  it  is  of  a  beauti- 
ful \iolot,  but  with  reflected  light  it  displays  a  tint  rivaling  in  brilliancy 
the  tail  of  a  peacock."— Boston  Journal  of  Chemistry. 

*  The  acid  may  be  considered  as  the  hydroxide  of  the  radical  phenyl, 
and  hence  is  sometimes  called  2)heHt/l  alcohol. 


224  ORGANIC     CHEMISTRY. 

antiseptic  and  disinfecting  properties.  It  is  one  of 
the  products  of  coal-tar  distillation,  and  forms  white 
crystals.  It  is  very  poisonous.  By  heating  it  with 
HNO3,  CgHa  (N03)30H,  picric  acid  is  formed.  This 
colors  a  rich  yellow,  and  is  a  very  popular  silk  dye. 
It  forms  salts  by  the  replacement  of  the  H  of  the 
OH  group,  e.g.  C6H2(N02)3.0K.  The  picrates  are  yel- 
low, explosive  salts.  Potassium  picrate  is  used  in 
making  certain  explosives. 

Among  the  other  products  obtained  by  distilling 
coal-tar  are :  Coal-tai'  Naphtha ;  this  is  a  volatile, 
limpid  oil,  with  a  peculiar  odor,  and  generalh^  a  light 
straw  color.  It  is  composed  of  several  hydrocarbons, 
and  is  very  inflammable.  Naphthalene  is  a  crystalline 
solid  occurring  in  beautiful  pearly  scales.  It  is 
especially  abundant  in  dead-oil,  and  may  be  formed 
by  passing  olefiant  gas  or  benzol  through  red-hot 
tubes.  Anthracene  accompanies  naphthalene  in  the 
latter  part  of  its  distillation.  It  is  also  a  white  solid. 
It  is  of  interest  since  the  coloring  principle  of  mad- 
der— alizarine — has  been  made  from  it.  Dead-oil  is 
used  for  preserving  timber ;  as  a  cement  for  roofs 
and  walls ;  for  oiling  machinery,  etc. 

The  Acids  of  this  group  contain  the  carboxy] 
group  — CO.OH,  like  the  acids  of  the  paraffine  series. 
Among  them  are  benzoic  acid,  CgHgCO.OH  ;  salicylic, 
acid,  CgH^.  (OH)  CO.OH,  both  of  which  are  used  in 
medicine,  the  latter  and  its  salts  being  especially  im- 
portant. 

Benzoic  Aldehyde,  CeHgCHO,  is  the  fragrant  oil 
of  bitter  almonds,  and  methyl  salicylate,   C6H4  (OH) 


THE     TERPENES     AND     CAMPHORS.  225 

CO.OCH3  (an  ethereal  salt),  is  the  natural  oil  of  the 
wintergreen. 

Toluene,  CgHgCHg  (methyl  benzene),  is,  next  to 
benzene,  the  most  important  of  the  hydrocarbons  of 
the  aromatic  group.  Like  benzene,  it  yields,  when 
treated  with  nitric  acid,  a  nitro-compound,  nitro- 
toluene,  C6H4NO2CH3,  which  is  reduced  by  nascent  H 
to  toluidine,  CeH^NHgCHg,  Toluene  is  always  present 
in  commercial  benzene,  and  hence  common  aniline 
contains  some  toluidine,  which  is  of  importance  in 
the  making  of  aniline  dyes.    ^^■ 


THE    TERPENES    AND    CAM- 
PHORS. 

The  Volatile  or  Essential  Oils. — The  volatile  oils, 
unlike  the  fixed,  make  no  soaps,  and  dissolve  readily 
in  alcohol  or  ether.  Their  solution  in  alcohol  forms 
an  essence. 

Sources.  —  The  volatile  or  essential  oils  are  of 
vegetable  origin.  They  are  found  in  the  petals  of  a 
flower,  as  the  violet ;  in  the  seed,  as  caraway ;  in  the 
leaves,  as  mint,  or  in  the  root,  as  sassafras.  Some- 
times several  kinds  of  oil  are  obtained  from  different 
parts  of  the  same  plant. — Example:  In  the  orange 
tree,  the  flower,  leaves,  and  rind  of  the  fruit  furnish 
each  its  own  variety.  The  perfume  of  flowers  is 
produced  by  these  volatile  oils ;  but  how  slight  a 
quantity  is  present  may  be  inferred  from  the  state- 


226  ORGANIC     CHEMISTRY. 

nient  that  "  one  hundred  pounds  of  fresh  roses  will 
give  scarcely  a  quarter  of  an  ounce  of  Attar  of 
Roses." 

Preparation. — In  the  peppermint  and  many  others, 
the  plant  is  distilled  with  water.  The  oils  pass  over 
with  the  steam,  and  are  condensed  in  a  cooler  con- 
nected with  the  "Mint  Still."  The  oil  floats  on  the 
surface  of  the  condensed  water,  and  may  be  re- 
moved. A  small  portion,  however,  remains  mingled 
with  the  latter,  which  thus  acquires  its  peculiar  taste 
and  odor,  constituting  what  is  termed  a  "  perfumed 
water."  In  some  flowers,  as  the  violet,  jasmine,  etc., 
the  perfume  is  too  delicate  to  be  collected  in  this 
manner.  They  are,  therefore,  laid  between  woolen 
cloths  saturated  with  some  fixed  oil.  This  absorbs 
the  essential  oil,  which  is  then  dissolved  by  alcohol. 
The  oil  of  lemon  or  orange  is  obtained  from  the 
rind  of  the  fruit  by  expression,  or  by  digesting  in 
alcohol. 

Composition. — C,oH|6  is  the  common  formula  of  a 
large  ninnber  of  these  oils.  Thus  the  oils  of  lemon, 
cloves,  juniper,  birch,  black  pepper,  ginger,  bergamot, 
turpentine,  cubebs,  oranges,  etc.,  with  many  others, 
are  isomeric. 

Oil  of  Turpentine  (C|oH,6),  is  a  type  of  this  group. 
It  is  made  by  distilling  pitch.  It  is  generally  called 
spirits  of  turpentine.  It  is  highly  inflammable,  and, 
owing  to  the  excess  of  C,  burns  with  a  great  smoke. 
Turpentine  is  used  in  making  varnishes  and  in  med- 
icine. By  the  union  of  two  atoms  of  its  H  with  an 
atom  of  the  0  of  the  air,  to  form  HgO,  it  is  converted 


THE     TERPENES     AND     CAMPHORS.  227 

into  rosin.*  Cartiphene  is  obtained  by  repeated  dis- 
tillation of  turpentine.  Burning-fluid  is  a  mixture  of 
camphene  and  alcohol.  In  the  heat  of  the  burning 
H  of  the  latter,  the  C  of  the  former  is  consumed, 
and  this  produces  a  bright  light.  The  tendency  of 
camphene  to  smoke  is  thus  diminished,  and  the 
illuminating  power  increased.  By  the  action  of  HCl 
on  turpentine  or  oil  of  lemons,  an  "artificial  cam- 
phor" is  produced,  which  much  resembles  common 
camphor. 

Camphor  (CioHigO)  is  obtained  by  distilling  chips 
of  the  camphor-tree  and  its  roots  with  water,  and 
condensing  the  vapors  on  rice-straw.  It  is  purified 
by  sublimation.  When  kept  in  a  bottle,  it  vaporizes, 
and  its  delicate  crystals  collect  on  the  side  toward 
the  light.  Taken  internally,  except  in  small  doses,  it 
is  a  virulent  poison.  Its  solution  in  alcohol  is  called 
"spirits  of  camphor."  If  HjO  be  added  to  this,  the 
camphor  will  be  precipitated  as  a  flour-like  powder,  f 

The  Resins  and  Balsams. — The  resins  are  gen- 
erally formed  from  the  essential  oils  by  a  slow 
oxidation. — Example :  Turpentine,  as  we  have  just 
seen,  is  changed  to  rosin,  a  resinous  substance.  If 
the   resin    is    dissolved    in    some    essential    oil,    it    is 


*  In  this  way,  the  turpentine  around  the  nozzle  of  a  bottle  in  which  it 
is  kept  becomes  first  sticky,  and  then  resinous.  Old  oil  should  not  be  taken 
to  remove  grease  spots,  as,  while  it  will  remove  one,  it  will  leave  another 
of  its  own. 

t  Though  camphor-gum  is  powdered  with  difficulty,  a  few  drops  of 
alcohol  will  remove  all  trouble.  Wlien  small  particles  of  powdered  camphor 
are  thrown  on  water  free  from  grease,  each  fragment  begins  to  dissolve 
with  a  remarkable  gyratory  motion,  which  is  instantly  checked  by  a  drop 
of  an  essential  oil  allowed  to  fall  upon  the  surface  of  the  liquid. 


228  ORGANIC     CHEMISTRY. 

called  a  balsam. — Example:  Pitch  is  a  balsam,  since 
by  distillation  it  is  separated  into  rosin  and  turpen- 
tine. They  generally  exude  from  incisions  in  trees 
and  shrubs,  in  the  form  of  a  balsam,  which  oxidizes 
on  exposure  to  the  air,  and  becomes  a  resin. — Ex- 
ample :  Spruce  gum.  The  resins  are  translucent  or 
transparent,  brittle,  insoluble  in  H2O,  ])ut  soluble  in 
ether,  alcohol,  or  any  volatile  oil,  and  form  varnishes. 
They  are  non-conductors  of  electricity,  and  burn  with 
much  smoke.  They  do  not  decay,  and  indeed,  have 
the  power  of  preserving  other  substances.* 

Rosin  constitutes  about  75  per  cent,  of  pitchy  a 
resinous  substance  which  exudes  from  incisions  made 
in  the  trunks  of  certain  species  of  pine.  It  is  used 
in  making  soaps,  to  increase  friction  in  violin-bows 
and  the  cords  of  clock-weights,  and  in  soldering. 

Lac  exudes  from  the  ficus-tree  of  the  East  Indies. 
An  insect  punctures  the  bark,  and  the  juice  flows 
out  over  the  insect,  which  works  it  into  cells  in 
which  to  deposit  its  eggs.  The  dried  gum  incrusting 
the  twigs  is  called  stich-lac ;  when  removed  from  the 
wood,  seed-lac ;  when  melted  and  strained,  shellac. 
The  liquefied  resin  is  dropped  upon  large  leaves,  and 
so  cools  in  broad,  thin  pieces.  Sealing-wax  is  made 
of  shellac  and  Venice  turpentine  ;  vermilion  or  red 
lead  being  added  to  give  the  red  color.  Shellac  is 
much  used  in  making  varnishes. 

Oum  Benzoin  also  exudes  from  a  tree  in  the  East 


*  For  this  reason  they  were  used  in  embalming  the  bodies  of  the  ancient 
Egyptians,  which,  after  the  lapse  of  two  thousand  years,  are  yet  found  dried 
into  mummies  in  their  mammoth  tombs— the  Pyramids. 


THE     TERPENES     AND     CAMPHORS.  229 

Indies.  It  is  a  source  of  benzoic  acid.  It  is  used  in 
fumigation  and  in  cosmetics,  and  on  account  of  its 
fragrant  odor  is  burnt  as  incense.* 

Amber  is  a  fossil  resin  which  has  exuded  in  some 
past  age  of  the  world's  history  from  trees  now  ex- 
tinct. It  is  sometimes  found  containing  various 
insects  perfectly  preserved,  which  were  without 
doubt  entangled  in  the  mass  while  it  was- yet  soft. 
These  are  so  beautifully  embalmed  in  this  trans- 
parent glass  that  they  give  us  a  good  idea  of  the 
insect  life  of  that  age.  Amber  is  cast  up  by  the  sea, 
principally  along  the  shores  of  the  Baltic ;  although 
it  is  also  found  in  beds  of  lignite.  It  is  commxonly 
translucent,  and  susceptible  of  a  high  polish.  It  is 
used  for  ornaments,  mouth-pieces,  necklaces,  buttons, 
etc, ;   and  is  an  ingredient  of  some  varnishes. 

Caoutchouc,  or  India-ruhher,  exudes  from  certain 
trees  in  South  America  as  a  milky  juiccf  The 
solvents  of  rubber  are  ether,  naphtha,  turpentine, 
chloroform,  carbon  disulphide,  etc.  It  melts,  but 
does  not  become  solid   on   cooling.     Freshly-cut  sur- 

*  Place  some  green  sprigs  under  a  glass  receiver,  and  at  the  bottom  a 
hot  iron,  on  which  sprinkle  a  little  benzoic  acid.  It  will  sublime  and 
collect  in  beautifully  delicate  crystals  on  the  green  leaves  above,  making  a 
perfect  illustration  of  winter  frost-work. 

t  The  globules  of  rubber  are  suspended  in  it  as  butter  is  in  milk.  The 
tree,  it  is  said,  yields  about  a  gill  per  day  from  each  incision  made.  A 
little  clay  cup  is  placed  underneath,  from  which  the  juice  is  collected  and 
poured  over  clay  or  wooden  patterns  in  successive  layers  as  it  dries.  To 
hasten  the  process  it  is  carried  on  over  large  open  fires,  the  smoke  of 
which  gives  to  the  rubber  its  black  color;  when  pure,  it  is  almost  white. 
When  nearly  hard,  the  rubber  will  receive  any  fanciful  design  which  may 
be  marked  upon  it  with  a  pointed  stick.  The  natives  often  form  the  clay 
into  odd  shapes,  as  bottles,  images,  etc.,  and  the  rubber  is  sometimes  ex- 
ported in  these  uncouth  forms. 


230  ORGANIC     CHEMISTRY. 

faces  readily  cohere  ;  this  property,  together  with  its 
power  of  resisting  most  re-agents,  renders  it  invalu- 
able to  the  chemist  in  making  flexible  joints  and 
tubes.  "It  loses  its  elastic  power  when  stretched  for 
a  long  time,  but  recovers  it  on  being  heated.  In  the 
manufacture  of  rubber  goods  for  suspenders,  etc., 
the  rubber  thread  is  drawn  over  bobbins,  and  left  for 
some  days  until  it  becomes  inelastic.  In  this  state  it 
is  woven,  after  which  a  hot  wheel  is  rolled  over  the 
cloth  to  restore  the  elasticity." 

Vulcanized  Ruhher  is  made  by  heating  caout- 
chouc with  a  small  amount  of  sulphur.  This 
constituted  Goodyear's  original  patent.*  It  is  less 
liable  to  be  hardened  by  cold,  or  softened  by  heat, 
and  admits  of  many  uses  to  which  common  rubber 
would  be  entirely  unsuited.  If  sulphurized  rubber 
be  heated  to  a  high  temperature,  it  becomes  a  hard, 
brittle,  black  solid  (vulcanite  or  ebonite),  capable  of 


♦  Mr.  Goodyear  had  been  experimenting  to  find  some  way  of  rendering 
rubber  insensible  to  heat  and  cold.  It  is  said  that  one  day,  while  talking 
with  a  friend,  ho  happened  to  drop  a  bit  of  S  in  a  pot  of  melted  rubber. 
By  one  of  those  happy  intuitions  which  seem  to  come  only  to  men  of 
genius,  he  watched  the  process,  and  to  his  amazement  found  that,  while 
the  appearance  of  the  rubber  was  the  same— clastic,  odorous,  and  tasteless- 
its  stickiness  was  gone,  and  it  had  gained  the  properties  he  so  much  de- 
sired. He  immediately  took  out  a  patent  in  this  country,  and  sailed  for 
England,  where,  instead  of  securing  his  secret  by  a  similar  patent,  he 
offered  to  sell  it  for  £10,000.  Charles  Hancock,  with  whom  he  had  been 
corresponding  for  several  years,  and  who  had  been  engaged  in  similar  ex- 
perimenting, resolved  to  discover  it  himself.  He  shut  himself  up  in  his 
laboratory,  and  went  to  work.  Disheartening  failures  marked  every  at- 
tempt. At  last  he  tried  S.  At  first,  he  did  not  succeed  ;  but,  persevering, 
he  finally  saw,  amid  the  stifling  fumes  of  brimstone,  the  soft  rubber 
metamorphosed  into  the  vulcanized  caoutchouc.  He,  too,  was  possessed  of 
the  secret,  and,  taking  out  a  patent,  reaped  the  reward  of  his  patient 
labor. 


THE     ALKALOIDS,  231 

a  high  polish,  which  is  used  for  knife-handles,  combs, 
buttons,  etc. 

Gutta-percha  resembles  caoutchouc  in  its  source, 
preparation,  and  appearance.  It  softens  in  hot  water, 
and  can  then  be  molded  like  wax.  When  cooled,  it 
assumes  its  original  solidity.  It  is  extensively  used 
in  taking  impressions  of  medals,  etc. 


THE     ALKALOIDS. 

The  alkaloids,  or  organic  bases,  as  they  are  called, 
are  the  bases  of  true  salts  found  in  many  plants. 
They  dissolve  very  slightly  in  H2O,  but  freely  in 
alcohol.  They  are  bitter  in  taste,  generally  have  a 
powerful  effect  on  the  animal  creation,  and  rank 
among  the  most  dangerous  poisons  and  valuable 
medicines.  All  the  alkaloids  contain  N  in  addition 
to  C  and  H,  and  many  also  contain  0.  Some  of  the 
alkaloids  have  been  obtained  by  artificial  means  in 
the  laboratory. 

Opium  is  the  dried  juice  of  the  poppy  plant,  which 
is  extensively  cultivated  in  Turkey  for  the  sake  of 
this  product.  Workmen  pass  along  the  rows  soon 
after  the  flowers  have  fallen  off,  cutting  slightly  each 
capsule.  From  these  incisions  a  milky  juice  exudes, 
and  collects  in  little  tears.  These  are  gathered,  and 
wrapped  in  leaves  for  the  market.  Opium  contains 
some  seventeen  different  alkaloids  in  combination 
with  at  least  two  acids.    In  small  doses,  opium  is  a 


232  ORGANIC     CHEMISTRY. 

sedative  medicine ;  in  larger  ones,  a  narcotic  poison. 
Laudanur)i  is  the  tincture  of  opium ;  and  paregoric, 
a  camphorated  tincture  flavored  with  aromatics. 

Opium  -  eating. — Opium  produces  a  powerful  in- 
fluence on  the  nervous  system.  It  stimulates  the 
brain  and  excites  the  imagination  to  a  wonderful 
pitch  of  intensity.  The  dreams  of  the  opium-eater 
are  said  to  be  vivid  and  fantastic  beyond  description. 
The  dose  must,  however,  be  gradually  increased  to 
repeat  the  effect,  and  the  result  is  most  disastrous. 
The  nervous  system  becomes  deranged,  and  no  relief 
can  be  secured  save  by  a  fresh  resort  to  this  baneful 
drug.*  Labor  becomes  irksome,  ordinary  food  dis- 
tasteful, and  racking  pains  torment  the  body. 

Morphine  {Morpheus,  the  god  of  sleep)  is  the 
chief  narcotic  principle  of  opium,  and  like  it  is  used 
to  alleviate  pain  and  produce  sleep.  It  is  usually 
given  as  a  sulphate  or  chloride. 

Quinine  is  prepared  from  Peruvian  bark.    A  tinct- 

*  In  time,  the  whole  system  becomes  so  impregnated  with  it  that  even 
large  additional  doses  fail  to  produce  the  delightful  effect  which  at  first  so 
fascinated  the  victim.  Then,  while  acting  ujHjn  the  nerves,  it  set  free  a 
vast  amount  of  vitality  and  energy,  but  now  it  has  satisfied  itself.  The 
subtle  alkaloid  has  affected  the  tissues  and  coatings  of  the  entire  internal 
organism.  If,  resolutely,  one  summons  his  enfeebled  will,  and  commences 
the  conflict,  an  agony  of  endurance,  which  defies  all  description,  is  before 
him.  The  whole  body  must  be  reorganized.  If,  too  weak  to  attempt  so 
terrible  a  struggle,  he  continues  the  use  of  the  fatal  drug,  he  moves  on 
directly  to  his  fate— the  opium-eater's  grave.  Paregoric,  laudanum,  mor- 
phine, and  the  different  preparations  of  opium,  are,  in  almost  every  case, 
taken  first  as  a  sedative  from  pain  or  fatiguing  labor,  with  no  thought 
of  becoming  addicted  to  their  use.  But  so  insinuating  is  it  that  the  vio- 
tim  forms  the  habit  ere  he  is  aware,  and  knows  he  is  a  slave  only  when 
he  attempts  to  cease  the  customary  dose.  No  person  can  be  too  careful 
in  beginning  the  use  of  a  narcotic  whose  influence  is  liable  to  become  so 
destructive. 


THE     ALKALOIDS.  233 

ure  of  the  ba.rk,  or  sulphate  of  quinia,  is  employed 
in  medicine  in  cases  of  fever  and  ague,  and  other 
periodic  diseases,  and  also  as  a  tonic. 

Nicotine  is  the  active  principle  of  the  tobacco 
plant,  of  which  it  forms  from  2  to  8  per  cent.  It  is 
volatile,  and  passes  off  in  the  smoke.  A  drop  will  kill 
a  large  dog.  It  probably  produces  many  of  the  ill 
effects  which  follow  the  use  of  tobacco. 

Strychnine  is  prepared  from  the  nux  vomica  and 
the  St.  Ignatius  bean.  It  is  also  a  constituent  of  the 
celebrated  upas  poison.*  "It  is  so  intensely  bitter 
that  one  grain  will  impart  a  flavor  to  twenty-five 
gallons  of  water.  One  thirtieth  of  a  grain  has  killed 
a  dog  in  thirty  seconds,  while  half  a  grain  has  been 
fatal  to  man." 

The  Chromatic  Test,  as  it  is  called,  consists  in 
placing  on  a  clean  porcelain  plate  a  drop  of  the 
suspected  liquid,  a  drop  of  H2SO4.,  and  a  crystal  of 
potassium  bichromate.  Mix  the  three  very  slowly 
with  a  clean  glass  rod.  If  there  be  any  strychnine 
present,  it  will  change  the  color  into  a  beautiful 
violet  tint,  passing  into  a  pale  rose.f 


*  "The  '  woorara,'  with  which  the  South  American  Indians  poison  their 
arrows,  is  allied  to  strychnine.  This  is  so  deadly  that  the  scratch  of  a 
needle  dipped  in  it  will  produce  death ;  yet  it  may  be  swallowed  with  im- 
pvmity . ' ' — MiT.LE  r. 

t  Strychnine  is  the  only  poison,  except  brucine  (and  that  also  is  ex- 
tracted from  n\ix  vomica),  that  produces  tetanus,  or  lock-jaw.  This  symp- 
tom proves  to  the  physician  that  death  has  been  caused  by  this  alkaloid. 
To  exhibit  the  effect  of  the  poison  a  frog  is  sometimes  brought  into  a  court- 
room, and  made  to  show  its  action.  So  sensitive  is  this  little  animal  that  if 
the  sixteen-thousandth  of  a  grain  of  strychnine  be  introduced  into  its  lungs, 
the  drug  will  render  it  violently  tetanic  in  about  ten  minutes. 


234  ORGANIC    CHEMISTRY. 

Caffeine  and  Theine  constitute  the  active  prin- 
ciple of  tea*  and  coffee,t  and  are  identical.  They 
crystallize  in  long,-  flexible,  silky  needles.  In  addi- 
tion, tea  contains  from  13  to  18  per  cent,  of  a 
form  of  tannin,  about  22  per  cent,  of  extractive 
matter,  some  coloring  substances,  and  a  volatile  oil 
which  gives  to  it  its  aromatic  odor  and  taste.  Coffee 
contains  about  14  per  cent,  of  oil  and  fat,  and  also 
an  essential  oil  which  is  developed  in  roasting,  and  is 
very  volatile,  so  that  it  will  soon  escape  unless  the 
coffee  be  kept  tightly  covered. 


*  7'ea-»'amwg'.— Tea-plants  resemble  in  some  respects  the  low  whortleberry 
bush.  They  are  raised  in  rows,  three  to  five  in  a  hUl,  very  much  as  corn  is 
with  us,  but  they  are  not  allowed  to  grow  over  one  and  a  half  feet  high. 
The  medium-sized  leaves  are  picked  by  hand,  the  largest  ones  being  left  to 
favor  the  growth  of  the  bushes.  Each  little  hill  or  clump  -will  furnish  from 
three  to  five  ounces  of  green  leaves,  or  about  one  ounce  of  tea,  in  the  course 
of  the  season.  The  leaves  are  first  wilted  in  the  sun,  then  trodden  in  baskets 
by  barefooted  men  to  break  the  stems,  next  rolled  by  the  hands  into  a  spiral 
shape,  then  left  in  a  heap  to  heat  again,  and  finally  dried  for  the  market. 
This  constitutes  Black  Tea,  and  the  color  would  be  produced  in  any  leaves 
left  thus  to  wilt  and  heat  in  heaps  in  the  open  air.  The  Chinese  always 
drink  this  kind  of  tea.  They  use  no  milk  or  sugar,  and  prepare  it,  not  by 
steeping,  but  by  pouring  hot  water  on  the  tea  and  allowing  it  to  stand  for 
a  few  minutes.  Whenever  a  friend  calls  on  a  Chinaman,  common  politeness 
requires  that  a  cup  of  tea  be  immediately  offered  him. 

0-reen  Tea  is  prepared  like  black,  except  that  it  is  not  allowed  to  ■wilt  or 
heat,  and  is  quickly  dried  over  a  fire.  It  is  also  very  frequently,  if  not 
always,  colored — cheap  black  teas  and  leaves  of  other  plants  being  added  in 
large  quantities.  In  this  country,  damaged  teas  and  the  "grounds"  left  at 
hotels  are  re-rolled,  highly  colored,  packed  in  old  tea-chests,  and  sent  out 
as  new  teas.  Certain  varieties  of  black  tea  even  receive  a  coating  of  black- 
lead  to  make  them  shiny. 

+  Coffee  is  the  seed  of  the  coffee  plant,  a  native  of  the  tropics.  The 
plant  is  very  prolific,  remaining  in  flower  eight  months  of  the  year  and 
usually  producing  three  harvests  annually.  The  fruit  resembles  the  cherry, 
but  contains  two  seeds  or  "beans"  instead  of  a  single  stone,  inclosed  in  a 
thick  leathery  skin.  The  drying  of  the  coffee  is  a  most  important  process. 
A.  shower  of  rain  will  discolor  the  beau  and  depreciate  its  value. 


DYES     AND     DYEING.  235 


DYES     AND     DYEING. 

Many  of  the  organic  coloring  principles  are  of 
vegetable  origin.  They  are  found  in  the  roots,  wood, 
bark,  flowers,  and  seeds  of  plants. 

Dyeing. — Very  few  of  the  colors  have  such  an 
affinity  for  the  fibers  of  the  cloth  that  they  will  not 
wash  out.  Those  which,  like  indigo,  will  dye  directly, 
are  called  substantive  colors.  But  the  majority  are 
adjective  colors,  which  require  a  third  substance 
having  an  attraction  for  both  the  coloring  matter 
and  the  cloth,  to  hold  them  together.  Such  sub- 
stances are  called  mordants  {mordeo,  to  bite),  because 
they  bind  the  dye  in  the  cloth,  thus  making  a  ''fast 
color."  The  most  common  mordants  are  alum,  salts 
of  tin  and  of  iron.  In  dyeing,  the  cloth  is  first 
dipped  into  a  solution  of  the  mordant,  and  then  into 
one  of  the  dye-stuff.  The  mordant,  by  means  of  a 
stamp,  may  be  applied  to  the  cloth  in  the  form  of  a 
pattern,  and,  when  it  is  afterward  washed,  the  color 
will  be  removed,  except  where  the  mordant  fixed  it 
in  the  printed  figure.  The  same  dye  will  produce 
•  different  colors  by  a  change  of  mordants. — Example: 
Madder,  with  iron,  gives  a  fine  purple  ;  with  alum,  a 
pink ;  and  with  iron  and  alum,  a  chocolate.  This 
principle  lies  at  the  basis  of  dyeing  "prints."* 

*  A  calico  printing-machine  is  very  complex.  The  cloth  passes  between 
a  series  of  rollers,  upon  which  the  corresponding  mordant  is  put,  as  ink  is 
on  type.  A  single  machine  sometimes  prints  from  twenty  sets  of  rollers ; 
yet  each  impression  follows  the  other  so  accurately  that,  when  the  cloth 
has  passed  throiigh,  the  entire  pattern  is  printed  upon  it,  with  the  different 
moraants,  more  perfectly  than  any  painter  could  do  it,  and  so  rapidly  that 


236  ORGANIC     CHEMISTRY. 

Coloring  Substances. — Madder  is  the  root  of  a 
plant  found  in  the  East,  and  extensively  cultivated 
elsewhere.  When  first  dug,  it  is  yellow,  but  by  ex- 
posure it  becomes  red.  It  is  used  in  dyeing  the 
brilliant  Turkey-red.  The  coloring  principle,  which 
is  named  alizarin,  is  identical  with  that  derived 
from  anthracene,  a  hydrocarbon  found  in  coal-tar 
(see  p.  224),  and  is  now  made  in  large  quantities 
from  that  source.  Cochineal  is  a  dried  insect  that  in 
life  feeds  upon  a  species  of  cactus  in  Central  America. 
The  coloring .  matter  is  called  Carmine.  It  yields  the 
brightest  crimson  and  purple  dyes.*  Brazil-ivood 
furnishes  a  red  which  is  not  very  permanent.  It  is 
used  for  making  red  ink.  The  indigo  of  commerce 
is  obtained  from  a  bushy  plant  found  in  the  East 
Indies.  By  fermenting  for  some  days  in  vats  of 
water,  the  coloring  matter  is  developed.  Reducing 
agents  change  indigo  into  a  soluble  and  colorless 
substance  by  the  absorption  of  H.f  It  is  then  called 
"white  indigo."  In  this  form  it  is  extensively  used 
in  dyeing.    The  cloth  becomes  permanently  colored  on 

a  mile  of  cloth  has  heen  printed,  with  fotir  mordants,  in  an  hour.  Tlie 
cloth,  when  it  leaves  the  printing-machine,  though  stamped  with  the  mor- 
dants in  the  form  of  the  figure,  betrays  nothing  of  the  real  design  until 
after  being  dipi)ed  in  the  dye,  which,  acting  on  the  different  mordants, 
brings  out  the  desired  colors.  The  print  is  now  washed,  glazed,  and  fitted 
for  the  market. 

*  The  purple  of  which  we  read  in  ancient  writings  was  a  secret  with  the 
Tyrians.  King  Hiram,  we  learn,  sent  a  workman  to  Solomon  skilled  in  this 
art.  The  dye  was  obtained  from  a  shell-fish  that  was  found  on  the  coast  of 
Phoenicia.  Each  animal  yielded  a  tiny  drop  of  the  precious  liquid.  "  A  yard 
of  cloth  dipped  twice  in  this  costly  dye  was  worth  Sl-'iO." 

+  Place  a  little  powdered  indigo  in  a  test-tube  of  HjO,  and  add  zinc 
filings  and  caustic  soda.  On  heating,  the  indigo  becomes  colorless.  If  it  is 
now  exposed  to  the  air  in  a  saucer,  it  will  turn  blue  again. 


DYES     AND     DYEING.  237 

exposure  to  the  air,  when  the  insoluble  blue  indigo 
is  formed  in  its  fibers.*  Logwood  is  so  named  be- 
cause imported  in  logs.  It  is  the  heart  of  a  South 
and  Central  American  tree.  With  a  mordant  of  iron, 
it  dyes  black.  I/itmus  is  obtained  from  a  variety  of 
lichens  common  along  the  southern  coast  of  Europe. 
Its  juice  is  colorless,  but  by  the  action  of  water,  air, 
and  NH3,  it  assumes  a  rich  purple  blue.  Leaf-green 
(chlorophyl),  as  found  in  plants,  is  a  resinous  sub- 
stance containing  several  coloring  matters.  It  seems 
to  be  developed  by  the  action  of  the  sunbeam.  Plants 
removed  from  a  dark  cellar  to  the  sunlight,  rapidly 
turn  green. 

Tannic  Acid,  tannin  (C|4H,o09),  is  found  in  the 
leaf  and  bark  of  trees. f — Example :  Oak,  hemlock. 
Nut-galls  are  excrescences  which  are  formed  by  the 
puncture  of  an  insect  on  the  leaves  of  a  certain 
species  of  oak.  Tannin  has  an  astringent  taste,  is 
soluble  in  water,  and  hardens  albuminous  substances, 
as  gelatin. 

Tanning. — After  the  hair  has  been  removed  from 
the  skins  by  milk  of  lime,  they  are  soaked  for  days, 
the  best  kinds  for  months,  in  vats  full  of  water  and 
ground  oak  or  hemlock  bark  (tan-bark).  The  tannic 
acid  of  the  bark  is  dissolved,  and,  entering  the  pores 
of  the  skin,  unites  with  the  gelatin,  forming  a  hard, 

*  One  of  the  triumphs  of  synthetical  chemistry  has  been  the  artificial 
preparation  of  indigo. 

+  This  astringent  principle  is  widely  diffused.  There  are  several  com- 
pounds wliich  possess  similar  properties,  yet  differ  in  chemical  composition. 
The  tannin  of  the  oak  is  called  quercUannic  acid  ;  that  of  nut-galls,  ffollotannie 
acid ;  that  of  tea,  theitannic,  and  that  of  coffee,  caffeotannic  add. 


238  ORGANIC     CHEMISTRY. 

insoluble  compound  which  is  the  basis  of  leather. 
Leather  is  blackened  by  washing  the  hide  on  one 
side  with  a  solution  of  copperas.  The  tannic  acid 
unites  with  the  iron,  forming  a  tannate  of  iron — an 
ink.  In  the  same  way,  drops  of  tea  on  a  knife-blade 
stain  it  black. 

Ink  is  made  by  adding  a  solution  of  nut-galls  to 
one  of  copperas.  The  iron  tannate  thus  formed  has 
a  pale  blue-black  color,  as  in  the  best  writing-fluids; 
by  exposure  to  the  air,  the  Fe  absorbs  more  0,  the 
ink  darkening  in  color  until  it  is  a  deep  black.  Gum 
is  added  to  thicken  and  regulate  the  flow  of  the  fluid 
from  the  pen.  Creosote,  or  corrosive  sublimate,  is 
used  to  prevent  moldiness.  Steel  pens  are  corroded 
by  the  free  H2SO4  contained  in  the  ink,  but  gold  pens 
are  not  affected  by  it.* 

Gallic  Acid  (CyHgOs)  is  best  prepared  from  nut- 
galls,  by  fermentation  of  the  tannic  acid  which  they 
contain.  Pyrogallic  acid  can  be  obtained  by  the 
sublimation  of  gallic  or  gallotannic  acid.  It  is  exten- 
sively used  in  photography  for  the  purpose  of  devel- 
oping the  latent  image  in  the  collodion  film  after 
exposure  to  the  action  of  the  light.     (See  p.  172.) 

Linseed  Oil  is  a  drying  oil,  as  it  is  termed — /.  f., 
it  absorbs  0  from  the  air,  and  hardens  by  exposure. 

*  The  following  is  an  instructive  experiment,  illustrating  the  manner  of 
making  ink,  of  removing  stains  with  oxalic  acid,  and  also  the  relative 
strength  of  the  acids  and  alkalies :  Take  a  large  test-tube,  and  add  the 
following  re-agents  in  solution,  cautiously,  drop  by  drop,  watching  the  result 
and  explaining  the  reactions :  1,  iron  sulphate  {copperas) ;  2,  tannic  acid 
{tannin) ;  3,  oxalic  acid  ;  4,  sodium  carbonate  {sal-soda) ;  5,  hydrochloric  acid 
{muriatic) ;  6,  ammonia  {hartshorn) ;  7,  nitric  acid  (aq^qfortis) ;  8,  caustic 
I)otash ;  0,  sulphuric  acid  {oil  of  vitriol.) 


THE     ALBUMINOUS     BODIES,  239 

It  is  expressed  from  flaxseed,  which  furnishes  about 
one  fifth  of  its  weight  in  oil.  Boiled  oil  is  made  by 
heating  the  crude  oil  with  litharge,  which  entirely 
dissolves  and  greatly  increases  the  drying  property  of 
the  oil.  Linseed  oil  is  used  in  mixing  paints  and 
varnishes.  Putty  consists  of  linseed  oil  and  whiting, 
well  mixed.  The  chief  ingredients  of  jyrinters'  inh 
are  linseed  oil,  heated  until  it  becomes  thick  and 
viscid,  and  lamp-black. 


THE     ALBUMINOUS     BODIES. 

These  are  albumin,  casein,  and  fibrin.  Owing  to 
the  complexity  of  their  composition,  no  satisfactory 
formula  can  be  assigned  to  them.  The  molecule  of 
albumin  has  been  stated  as  C72H ,  ,oN,8S022,  but  it  is 
very  uncertain.* 

Albumin  is  found  nearly  pure  in  the  whites  of 
eggs,f  hence  the  name  {alhus,  white).  It  exists 
as  a  liquid  in  the  sap  of  plants,  the  humors  of 
the  eye,  serum  of  the  blood,  etc. ;  and  as  a  solid 
in  the  seeds  of  plants,  and  the  nerves  and  brains 
of  animals.  X 


*  Many  chemists  regard  albumin,  casein,  fibrin,  etc.,  as  isomeric,  and 
capable  of  being  converted  by  the  vital  force  one  into  the  other.  These 
bodies  are  sometimes  called  ProMn  {protos,  first)  on  the  supposition  that 
they  were  derived  from  a  single  azotized  principle  named  protein. 

t  strange  to  say,  "  the  venom  of  the  rattlesnake  is  isomeric  with  the 
'  the  whites  of  eggs.'  " 

t  This  principle  is  of  very  great  importance,  as  albumin  may  thus  be 
carried  by  the  blood  through  the  system,  but  when  once  deposited  it  can 
not  b''  dissolved  and  washed  away  again. 


240  ORGANIC     CHEMISTRY. 

Properties. — It  is  soluble  in  cold,  but  insoluble  in 
hot  H2O.  At  a  temperature  of  about  140°  F,,  it 
coagulates.  This  change  we  always  see  in  the  cooking 
of  eggs ;  yet  nothing  is  known  of  its  cause.  Alcohol, 
corrosive  sublimate,  acids,  creosote,  and  solutions  of 
copper,  lead,  silver,  etc.,  have  the  power  to  coagulate 
albumin.  In  cases  of  poisoning  by  these  substances, 
the  white  of  eggs  is  therefore  a  valuable  antidote,  as 
it  wraps  them  in  an  insoluble  covering,  and  so  pro- 
tects the  stomach. 

Casein  {caseus,  chees§)  is  found  in  the  curd  of 
milk.  In  the  presence  of  an  acid  it  coagulates,  and 
thus  milk  curdles  after  it  sours.  Rennet  (the  dried 
stomach  of  a  calf)  is  used  to  coagulate  milk  in  the 
process  of  cheese-making,  but  the  cause  of  its  action 
is  not  understood. 

Milk  is  a  natural  emulsion,  composed   of  exceed- 
ingly minute  globules  diffused  through  a  transparent 
liquid.    The  globules  consist  of  a 
thin  envelope  of   casein  filled  with  ^'"'  '^" 

butter.    Being  a  trifle  lighter  than 
H2O,  they  rise   to  the   surface  as 
cream.      Churning    breaks     these 
coverings,  and  gathers  the  butter 
into  a  mass.    Milk  contains  some 
sugar,  which,  by  a  peculiar  change  ^^^^  „^^^  jfl^^. 
termed   "  lactic    fermentation,"    is 
converted  into  lactic  acid.    The  casein  seems  to  act 
as  a  ferment  in  hastening  this  oxidation,  and,  by  its 
decay,  produces  the  offensive  odor.    In  the  "souring" 
of    milk,   the   milk-sugar    (C12H24O,,)    disappears,   and 


THE     ALBUMIlSrOUS     BODIES. 


241 


Fig.  74. 


Fibrin,  or  Musch: 


lactic  acid  (CaHgOg)  gradually  takes  its  place.  It  is 
an  excellent  illustration  of  a  complex  molecule  break- 
ing up  into  simple  ones. 

Fibrin  constitutes  chiefly  the  fibrous  portion  of 
the  muscles.  If  a  piece  of  lean  beef  be  washed  in 
clean    HgO    until    all    the  red    color    disappears,    the 

mass  of  white  tissue  which 
will  remain  is  called  fibrin. 
Like  albumin,  it  exists  in 
two  forms — as  a  liquid  in  the 
blood,  and  as  a  solid  in  the 
flesh.  The  clotting  of  blood 
is  due  to  the  coagulation  of 
the  fibrin.  (See  "  Physiol- 
ogy,"  p.  108.) 
Vegetable  Albuminoids. — Vegetables  contain  sub- 
stances which  are  scarcely  to  be  distinguished  from 
the  albuminous  bodies  derived  from  animal  sources. 
If  wheat  flour  be  made  into  a  dough,  and  then 
kneaded  in  water  until  the  soluble  portion  is  washed 
away,  the  tough,  sticky  mass  which  will  remain  is 
called  gluten.  It  is  a  nitrogenous  substance,  allied  to 
albumin.  It  exists  most  abundantly  in  the  bran  of 
cereal  grains. 

By  treating  peas  as  we  do  potatoes  in  forming 
starch,  and  then  adding  a  little  acid  to  the  water 
which  is  left  after  the  starch  settles,  an  albuminous 
substance  is  deposited,  which  is  thought  to  be  iden- 
tical with  casein.  The  Chinese  use  it  largely  for 
cheese.  It  is  found  abundantly  in  the  seeds  of  peas, 
beans,  etc.,  and  is  termed  legumin. 


242  ORGANIC     CHEMISTRY. 

Putrefaction. — Owing  to  the  complex  structure  of 
albuminous  substances,  and  the  presence  of  N,  they 
readily  oxidize,  and  form  new  and  simple  compounds. 
This  breaking  up  of  the  organic  structure  is  called 
putrefaction,  and  is  but  a  special  kind  of  fermenta- 
tion. The  activity  of  the  ferment  probably  explains 
the  danger  physicians  incur  in  dissecting  dead 
bodies.  The  least  portion  of  the  decomposing  mat- 
ter entering  the  flesh,  through  a  scratch,  is  liable 
to  be  fatal.  The  absence  of  HgO  retards  chemical 
change,  and,  therefore,  meats,  apples,  etc.,  are  pre- 
served by  drying.  *  Salt  acts  by  hardening  the 
albumin,  by  absorbing  the  juice  of  the  meat,  and  by 
covering  as  brine,  and  so  warding  off  the  attacking 
0  ;  but  as  it  dissolves  some  of  the  salts  and  other 
valuable  elements,  it  makes  the  meat  less  nutritious. 


Gelatin. — Hot   water    dissolves    a    substance  from 
animal  membranes,  skin,  tendons,  and  bones,t  which, 

*  The  cold  also  protects  from  chemical  change.  The  bodies  of  mam- 
moths have  been  found  in  the  frozen  soil  of  the  Arctic  regions  so  perfectly 
preserved  that  the  dogs  ate  the  flesh.  How  long  the  animals  had  been 
theie  we  can  not  tell,  but  certainly  for  ages.  In  1861  the  mangled  remains 
of  three  guides  were  found  at  the  foot  of  the  Glacier  de  Boisson,  in  Switzer- 
land. They  had  been  lost  in  an  avalanche  on  the  plateau  of  Mont  Blanc, 
forty-one  years  before. 

+  Analysis.     (Berzelius.) 

Gelatin 32.17 

Blood-vessels 1.13 

Phosphate  of  lime 51.04 

Carbonate  of  lime 11.30 

Fluoride  of  calcium 2.00 

Phosphate  of  magnesia 1.16 

Chloride  of  sodium 1.20 

100.00 
+  Bones  consist  of  organic  and  mineral  matter  combined.    By  soaking  a 


DOMESTIC     CHEMISTRY.  243 

on  cooling,  forms  a  yielding,  tremulous  mass  called 
gelatin.  In  calves-foot  jelly,  soups,  etc.,  it  is  well 
known,*  Olue  is  a  gelatin  made  from  bones,  hoofs, 
horns,  etc.,  by  boiling  in  HgO,  and  then  evaporating 
the  solution.  Isinglass  is  a  very  pure  gelatin,  ob- 
tained from  the  air-bladders  of  the  cod,  sturgeon, 
and  other  fish.  Size  is  a  gelatin  prepared  from  the 
parings  of  parchment.  It  is  used  for  sizing  paper 
in '  order  to  fill  up  the  pores  and  prevent  the  ink 
from  spreading,  as  it  does  on  unsized  or  blotting- 
paper. 


DOMESTIC     CHEMISTRY. 

In"  the  chemistry  of  housekeeping  there  are  some 
points  not  yet  mentioned  which  may  now  be  profit- 
ably discussed. 

Making  Bread. — Flour  consists  of  starch,  gluten, 
and  a  little  dextrin  and  sugar. 

The  oily  matter  and  the  salts — of  which  there  are 
from  1  to  2  per  cent,  in  wheat  —  are  contained 
mainly  in  the  bran.  The  process  of  making  the 
"  sponge  "  is  purely  mechanical.  When  the  sponge  is 
set  in  a  warm  place  to  rise  (as  heat  favors  chemical 

bone  in  HCl  the  mineral  matter  will  all  be  dissolved,  and  the  organic  matter 
left  in  the  original  shape  of  the  bone,  but  soft  and  pliable.  If,  instead,  the 
bone  be  burned  in  the  fire,  the  organic  matter  will  be  removed,  and  the 
mineral  left  white  and  porous.    (See  "  Physiology,"  p.  20.) 

*  As  an  article  of  food  it  is  of  very  little  nutritive  value.  It  may  answer 
to  dilute  a  stronger  diet,  bxit  of  itself  does  little  to  build  up  the  body  of  an 
invaUd.  Beef-tea,  even,  is  now  thought  to  have  little  nourishing  property, 
its  principal  oflace  being  to  act  as  a  stimulant. 


244  ORGANIC     CHEMISTRY. 

change),  the  yeast,  yeast-cake,  or  emptyings,*  as  the 
case  may  be,  induce  a  rapid  fermentation,  converting 
the  sugar  into  alcohol  and  COg.  This  gas  is  diffused 
through  the  mass,  and,  being  retained  by  the 
tenacious  dough,  causes  it  to  "  rise " — i.  e.,  to  swell 
and  become  porous.  The  next  step  includes  the 
addition  of  flour,  and  a  laborious  process  of  "knead- 
ing." The  latter  diffuses  the  half-fermented  sponge 
through  the  dough ;  it  also  breaks  up  into  smaller 
ones  the  bubbles  of  gas  entangled  in  the  gluten,  and 
makes  the  bread  fine-grained.  After  a  second  rising, 
the  dough  is  molded  into  loaves,  which  are  set  aside 
to  perfect  the  fermentation.  AVhen  they  are  finally 
placed  in  the  oven,  the  heat  expands  the  CO2,  and 
increases  the  porosity  of  the  bread ;  the  starch 
granules  are  broken  up ;  and  the  alcohol  is  vapor- 
ized, and  it  and  the  HgO  partly  driven  off.  The 
surface  becomes  dry  and  hard,  and,  losing  a  part  of 
its  chemically  combined  water,  is  partially  converted 
into  a  substance  allied  to  caramel,  thus  forming  the 
crust.*  If  the  temperature  of  the  oven  is  right, 
the  cells  of  the  bread  will  have  sufficient  strength  to 


*  Milk-emptjings  are  sometimes  used  in  making  bread.  In  this  case  the 
mixture  of  flour  and  milk,  kept  at  a  temperature  of  about  "blood  heat," 
rapidly  develops  yeast,  which  produces  fermentation.  If  the  heat  is  much 
above  this,  the  plant  will  be  killed,  and  the  milk  be  merely  turned  to  lactic 
acid.  Oftentimes,  too,  the  side  of  the  dish,  near  the  fire,  may  be  warm  enough 
to  produce  yeast,  and  to  generate  CO,  and  alcohol,  Avhile  on  the  opposite  side 
lactic  acid  is  being  formed.  A  iiniform  temperature  is  necessary,  and  this 
can  best  be  obtained  by  placing  the  dish  of  emptyings  in  a  kettle  of  warm 
water  on  the  stove  hearth. 

t  A  shiny  coat  is  given  to  the  loaf  ("rusk")  by  moistening  the  crust 
after  the  bread  is  baked,  thus  dissolving  some  of  the  dextrin,  which  is 
also  contained  in  the  crust.    This  quickly  dries  on  returning  it  to  the  oveu. 


DOMESTIC     CHEMISTRY.  245 

retain  their  form  after  the  gas  and  vapors  have 
escaped.  If  the  heat  is  not  sufficient,  or  if  there 
is  too  much  water  in  the  dough,  the  COg  escapes, 
the  cells,  not  being  sufficiently  hardened,  collapse, 
and  the  bread  is  "slack-baked."  If  the  oven  is 
too  hot,  the  crust  forms  too  quickly  over  the  sur- 
face of  the  loaf,  preventing  the  escape  of  the  CO2, 
which  accumulates  at  the  center,  making  the  loaf 
hollow. 

Stale  Bread. — New  bread  consists  of  about  45  per 
cent,  water.  In  stale  bread  this  disappears,  but  may 
be  brought  to  view  again  by  heating  the  loaf  in  a 
close  tin  vessel. 

Aerated  Bread  is  made  in  the  following  manner : 
Flour  and  salt  are  put  in  a  revolving  copper  globe, 
into  which  HgO,  charged  with  CO2,  is  admitted. 
When  well  mixed,  a  stop-cock  is  turned,  and  the 
dough  is  driven  out  by  the  elastic  force  of  the  gas, 
into  pans  ready  for  baking. 

Sour  Bread  results  from  a  neglect  to  arrest  the 
first  stage  of  the  fermentation,  thus  allowing  the 
second  stage  to  commence,  and  acetic  acid  to  be 
formed.  The  acid  is  neutralized  by  an  alkali,  as  sale- 
ratus,  or  soda. 

Griddle-cakes  are  raised  b}-  the  addition  of  some 
ferment,  as  yeast ;  but  the  second,  or  acetic  stage,  is 
always  reached.  The  "  batter  "  then  tastes  sour,  and 
is  sweetened  by  saleratus  or  soda.  The  acetic  acid 
combines  with  the  metallic  base,  forming  a  harmless 
salt,  which  remains,  while  the  CO2  bubbles  up  through 
the  batter,  making  it  "  light." 


246  ORGANIC     CHEMISTRY. 

Raising  Biscuit. — In  raising  biscuit  or  cake,  soda 
and  cream  of  tartar*  are  most  commonly  used.  The 
CO2  is  set  free,  and,  escaping  as  a  gas,  makes  the 
dough  porous,  while  the  sodium  and  potassium 
tartrate  (Rochelle  salt)  which  is  formed,  remains. 
Ordinary  "  baking-powders  "  are  merelj^  cream  of  tar- 
tar and  soda.  A  variet}'  invented  by  Professor 
Horsford  contains  acid  calpium  phosphate  (see  note, 
p.  142);  this,  reacting  upon  the  "soda,"  forms  cal- 
cium and  sodium  jjhosphates,  both  of  which  are 
materials  for  bone-making. f  Soda  and  HCl  are  also 
used  in  baking.  By  heat,  these  ingredients  are  re- 
solved into  H2O,  CO2,  and  NaCl.  The  HgO  and  CO2 
raise  the  broad,  while  the  common  salt  seasons  it. 
There  is  a  difficulty  in  procuring  pure  acid,  and  in 
mixing  the  ingredients  in  their  combining  propor- 
tions. Sal-volatile  (ammonium  sesquicarbonate,  p. 
137)  is  often  used  by  bakers  for  raising  cake.  This 
should  volatilize  into  two  gases,  NH3  and  COg,  on  the 
application  of  heat,  but  in  practice  a  portion  is  com- 
monly left  hidden  in  the  cake,  and  may  be  detected 
by  the  odor.  Alum  is  often  employed  by  bakers  to 
whiten  bread,  and  to  improve  the  appearance  of 
bread  made  from  inferior  flour. 

*  Cream  of  tartar  is  often  adulterated  with  plaster,  lime,  chalk,  or  flour.  By 
dissolving  in  water,  these  impurities  can  be  detected,  as  they  form  an  insoluble 
precipitate  ;  but  in  milk,  as  commonly  used  in  cooking,  they  are  not  noticed. 

t  It  is  doubtful  whether  ordinary  yeast-powders,  or  cream  of  tartar  and 
soda,  make  as  healthful  food  as  the  regular  process  of  fermentation.  There 
is  frequently  a  portion  of  the  powders  left  uncombined,  and  always  a  salt 
formed  which  may  perhaps  interfere  with  the  action  of  the  giistric  juice. 
Sometimes,  indeed,  we  find  biscuit  and  cake  yellow,  and  even  spotted  with 
bits  of  saleratus ;  yet,  through  a  false  economy,  such  food  is  too  often 
"  eaten  to  save  it." 


PRACTICAL     QUESTIONS.  247 

Toasting  Bread.  —  By  toasting,  bread  becomes 
much  more  digestible,  as  the  starch  is  converted 
largely  into  dextrin,  which  is  soluble.  The  charcoal 
which  may  be  formed  when  the  heat  has  disorgan- 
ized the  bread  and  driven  off  the  water,  also  acts 
favorably  on  the  stomach  by  absorbing  in  its  pores 
noxious  gases,  as  in  "crust-coffee." 

Cooking  Potatoes. — A  raw  potato  is  indigestible, 
but  by  cooking  the  starch  granules  absorb  the  water 
of  the  potato,  burst,  and  make  it  "mealy."  If  the 
potato  contains  more  H2O  than  the  starch  can  imbibe, 
it  is  called  "watery." 


PRACTICAL    QUESTIONS. 

1.  How  would  you  prove  the  presence  of  tannin  in  tea? 

2.  How  would  you  test  for  Fe  in  a  solution? 

3.  Why  can  we  settle  coflfee  with  an  egg? 

4.  How  would  you  show  the  presence  of  starch  in  a  potato? 

5.  Why  is  starch  stored  in  the  seed  of  a  plant? 

6.  Why  are  unbleached  cotton  goods  dark  colored? 

7.  Why  do  beans,  rice,  etc.,  swell  when  cooked  ? 

8.  Why  does  decaying  wood  darken? 

9.  How  would  you  show  that  C  exists  in  sugar? 

10.  Why  do  fruits  lose  their  sweetness  when  over-ripe? 

11.  Wliy  does  maple-sap  lose  its  sweetness  when  the  leaf  starts? 

12.  Should  yeast  cakes  be  allowed  to  freeze? 

13.  Why  will  wine  sour  if  the  bottle  be  not  well  corked? 

14.  Why  can  vinegar  be  made  from  sweetened  water  and  brown  paper? 

15.  "Why  should  the  \inegar-barrel  be  kept  in  a  warm  place? 

16.  Why  does  "scalding"  check  the  "working"  of  preserves? 

17.  Is  the  oxalic  acid  in  the  pie-plant  poisonous? 

18.  How  may  ink-stains  be  removed? 

19.  Why  is  leather  black  on  only  one  side? 

20.  Why  do  drops  of  tea  stain  a  knife-blade  ? 

21.  Why  will  not  coffee  stain  it  in  the  same  way? 

22.  Why  does  writing-fluid  darken  on  exposiire  to  the  air? 


248  ORGANIC     CHEMISTRY. 

23.  Why  does  ink  corrode  steel  pens? 

24.  How  does  a  bird  obtain  the  CaCOj  for  its  egg-shells? 

25.  Why  will  tallow  make  a  harder  soap  than  lard? 

26.  Why  does  new  soap  act  on  the  hands  more  than  old? 

27.  What  is  the  shiny  coat  on  certain  leaves  and  fruits? 

28.  Why  does  turpentine  b;irn  with  so  much  smoke? 

29.  Why  is  the  nozzle  of  a  turpentine  bottle  so  sticky? 

30.  Why  does  kerosene  give  more  light  than  alcohol? 

31.  What  is  the  antidote  to  oxalic  acid?    "Why? 

32.  Would  you  weaken  camphor  spirits  with  water? 

33.  What  is  the  difference  between  rosin  and  resin? 

34.  Why  does  ekim-milk  look  blue  and  new  milk  white? 

35.  Why  does  an  ink-spot  turn  yellow  after  washing  with  soap? 


CONCLUSION. 

Chemistry  of  the  Sunbeam. — The  various  plant- 
products  of  which  we  have  spoken  in  Organic 
Chemistry,  when  burned,  either  in  the  body  as  food 
or  in  the  air  as  fuel,  give  off  heat.  This  was 
garnered  in  the  plant  while  growing,  and  came  from 
that  great  source  of  heat — the  sun.  Thus  all  vegeta- 
tion contains  the  latent  heat  of  the  sunbeam,  ready 
to  be  set  free  upon  its  own  oxidation.  The  coal, 
even,  derived  as  it  is  from  ancient  vegetation,  hidden 
away  in  the  earth,  is  thus  a  mine  of  reserved  energy. 
Those  black  diamonds  we  use  as  fuel  become,  in  the 
eye  of  science,  crystallized  sunbeams,  fagots  of  energy, 
ready  to  impart  to  us  at  any  moment  the  heat  of 
some  old  Carboniferous  day.  A  field  of  growing 
wheat  reaches  out  its  tiny  arms,  and,  tangling  in 
stalk  and  grain  the  heat  of  sultry  mid-summer,  re- 
tains it  against  the  bleak  December.  The  oil-w^ell 
spouts  not  alone  unsavory  kerosene,  but  liquid  sun- 
beams, the  gathered  store  of  a  geologic  age.  As  we 
warm  ourselves  by  our  fires,  or  sit  and  read  by  our 
oil  and  gas  lights,  how  strange  the  thought  that 
their  light  and  heat  streamed  down  upon  the  earth 
ages  ago,  were  absorbed  by  the  grotesque  leaves  of 
the  old  coal  forests,  and  kept  safely  stored  away  by 


250  ORGANIC     CHEMISTRY. 

a  Divine  care  in  order  to  provide  for  our  comfort !  The 
present  warmth  of  our  bodies  ah  came  from  tlie  same 
source — the  sun.  It  mostly  fell  in  the  sunbeams  of 
last  summer  upon  our  gardens  and  fields,  was  pre- 
served in  the  potatoes,  cabbage,  corn,  etc.,  we  have 
eaten  as  food,  and  to-day  reappears  as  heat  and 
motion.  Every  blow,  every  breath,  and  every  step, 
are  but  transformations  of  solar  rays,  and  can  be 
estimated  in  sunshine. 

The  Sun  the  Source  of  Power. — The  sun  warms, 
enlivens,  and  animates  the  earth.  In  the  laboratory 
of  the  leaf,  he  produces  the  most  wonderful  chemical 
changes.  We  see  his  handiwork  in  the  Iniilding  of 
the  forest,  the  carpeting  of  the  meadow,  and  the 
tinting  of  the  rose.  On  the  ladder  of  the  sunbeam, 
water  climbs  to  the  sky,  and  falls  again  as  rain. 
The  very  thunder  of  Niagara  is  but  the  sudden  un- 
bending of  the  spring  that  was  first  coiled  by  the 
sun  in  the  evaporation  from  the  ocean.  Up  to  the 
sun,  then,  we  trace  all  the  hidden  manifestations  of 
power.  Yet  the  energy  that  produces  such  intricate 
and  wide-extended  changes  is  only  one  twenty-three 
hundred  millionth  part  of  the  tide  that  flows  in 
every  direction  from  this  great  central  orb.  But 
what  is  our  sun  itself  save  a  twinkling  star  beside 
great  suns  like  Sirius,  Regulus,  and  Procyon,  whose 
brilliancy  in  the  far-off  regions  of  space  drowns  our 
little  sun  as  the  dazzling  light  of  day  does  the 
smoldering  blaze  of  some  wandering  hunter? 

Changes  of  Matter. — Chemical  changes  are  taking 
place  wherever  we  look — on   land   or  sea.     The  hard 


CONCLUSION.  251 

granite  crumbles  and  molders  into  dust.  The  stout 
oak  draws  in  the  air,  and  solidifies  it ;  takes  up  the 
earth,  and  vitalizes  it ;  changes  all  into  its  own 
structure,  and  proudly  stands  monarch  of  the  forest. 
But  in  time  its  leaves  turn  yellow  and  sere ;  its 
branches  crumble ;  itself  totters,  falls,  and  dis- 
appears. Our  bodies  seem  to  us  comparatively 
stable,  but,  with  the  rock  and  the  oak,  they  too 
pass  away.  All  Nature  is  a  torrent  of  ceaseless 
change.  We  are  but  parts  of  a  grand  system,  and 
the  elements  we  use  are  not  our  own.  The  water 
we  drink  and  the  food  we  eat  to-day  may  have  been 
used  a  thousand  times  before,  and  that  by  the  vilest 
beggar  or  the  lowest  earth-worm.  In  Nature  all  is 
common,  and  no  use  is  base.  Those  particles  of 
matter  we  so  fondly  call  our  own,  and  decorate  so 
carefully,  a  few  months  since  may  have  dragged 
boats  on  the  canal,  "or  waved  in  the  meadow  as  grass 
or  corn.*    From  us  the}^  will  pass  on  their  ceaseless 

*  The  truth  that  matter  passes  from  the  animal  back  to  the  vegetable, 
and  from  the  vegetable  to  the  animal  kingdom  again,  received,  not  long 
since,  a  curious  illustration.  'For  the  purpose  of  erecting  a  suitable  monu- 
ment in  memory  of  Roger  Williams,  the  founder  of  Ehode  Island,  his 
private  burying-ground  was  searched  for  the  graves  of  himself  and  wife. 
It  was  found  that  every  thing  had  passed  into  oblivion.  The  shape  of  the 
coflins  coidd  only  be  traced  by  a  black  line  of  carbonaceous  matter.  The 
rusted  hinges  and  nails,  and  a  round  wooden  knot,  alone  remained  in  one 
grave ;  while  a  single  lock  of  braided  hair  was  found  in  the  other.  Near 
the  graves  stood  an  apple-tree.  This  had  sent  down  two  main  roots  into 
the  very  presence  of  the  coffined  dead.  The  larger  root,  pushing  its  way  to 
the  precise  spot  occupied  by  the  skull  of  Roger  Williams,  had  made  a  tiirn 
as  if  passing  around  it,  and  followed  the  direction  of  the  backbone  to  the 
hips.  Here  it  divided  into  two  branches,  sending  one  along  each  leg  to 
the  heel,  when  both  turned  upward  to  the  toes.  One  of  these  roots  formed 
a  slight  crook  at  the  knee,  which  made  the  whole  bear  a  striking  resem- 
blance to  the  human  form.    (These  roots  are  now  deposited  in  the  museum 


252  ORGANIC     CHEMISTRY. 

round  to  develop  other  forms  of  vegetation  and  life, 
"whereby  the  same  atom  may  freeze  on  arctic  snows, 
bleach  on  torrid  plains,  be  beauty  in  the  poet's 
brain,  strength  in  the  blacksmith's  arm,  or  beef  on 
the  butcher's  block.  Hamlet  must  have  been  some- 
what more  of  a  chemist  than  a  madman  when  he 
gravely  assured  the  king  that  "man  may  fish  with 
the  worm  that  hath  eat  of  a  king,  and  eat  of  the 
fish  that  hath  fed  of  the  worm." 

Shakespeare  expresses  the  same  chemical  thought 
when  he  again  makes  Hamlet  say: 

"  Imperious  Csesar,  dead  and  turned  to  clay, 
Might  stop  a  holo  to  keep  the  wind  away. 
Oh !   that  the  earth  which  Icept  the  world  in  awo 
Should  patch  a  wall  to  expel  the  winter's  flaw  1 " 

Or  when  he  makes  Ariel  sing: 

-  "  Full  fathom  five  thy  father  lies : 
Of  his  bones  are  coral  made ; 
Those  are  pearls  that  were  his  eyes; 
Nothing  of  him  that  doth  fade 
But  doth  suffer  a  sea  change 
Into  some  thing  rich  and  strange." 

Life  and  Death  aix;  thus  throughout  nature   com- 
mensurate with  and  companions  of  each  other.    Oxy- 

of  Brown  University.)  There  were  the  graves,  but  their  occupants  had  dis- 
appeared ;  the  bones  even  had  vanished.  There  stood  the  thief— the  guilty 
apple-tree — caught  in  the  very  act  of  robberj'.  The  spoliation  was  complete. 
The  organic  matter — the  flesh,  the  bones,  of  Roger  Williams— had  passed 
into  an  apple-tree.  The  elements  had  been  absorbed  by  the  roots,  trans- 
muted into  woody  fiber,  which  could  now  be  bumod  as  fuel,  or  carved  into 
ornaments;  had  bloomed  into  fragrant  blossoms,  which  had  deliglited  the 
eye  of  passers-by,  and  scattered  the  sweetest  perfume  of  spring;  more  than 
that— had  been  converted  into  luscious  fruit,  which,  from  year  to  year,  had 
been  gathered  and  eaten.  How  pertinent,  then,  is  the  question,  "Who  ate 
Koger  Williams?" 


CONCLUSION.  253 

gen  is  the  destroyer,  and  the  sunbeam  the  builder. 
Oxygen  tears  down  every  Uving  structure,  and  would 
bring  all  things  to  rest  in  ashes.  The  sunbeam  re- 
invigorates,  rebuilds,  and  rescues  from  the  grasp  of 
decay.  Though  they  seem  to  be  antagonists,  oxygen 
and  the  sunbeam  really  work  in  harmony,  and  each 
supplements  the  labor  of  the  other.  Death  alone 
makes  life  possible. 

Thus  we  have  traced  some  of  the.  wonderful  proc- 
esses by  which  this  world  has  been  arranged  to 
supply  the  varied  wants  of  man.  Wherever  we  have 
turned,  we  have  found  proofs  of  a  Divine  care  plan- 
ning, conforming,  and  directing  to  one  universal  end, 
while  from  the  commonest  things,  and  by  the  sim- 
plest means,  the  grandest  results  have  been  attained. 
Thus  does  Nature  attest  the  sublime  truth  .of  Revela- 
tion, that  in  all,  and  through  all,  and  over  all,  the 
Lord  God  omnipotent  reigneth. 


IV. 

Appendix 


TABLE     OF    THE     ELEMENTS 


Aluminium 

Antimony  (Stibium). 

Argon 

Arsenic 

Barium  

Bismuth  

Boron 

Bromine 

Cadmium 

Caesium  

Calcium , 

Carbon 

Cerium 

Chlorine  

Chromium 

Cobalt 

Columbium 

Copper  (Cuprum) 

Erbium  

Fluorine  

(3-adolinium 

Gallium 

(3^ermanium 

Glucinura 

Q-old  (Aurum) 

Helium 

Hydrogen 

Indium 

Iodine 

Iridium  

Iron  fPerrum) 

Lanthanum 

Lead  (Plumbum) 

Lithium 

Magnesium  

Manganese 

Mercury       (Hydrar-  < 
gyrum) ) 


Symbol. 

Atomic 
Weight. 

Al 

27 

Sb 

120 

A 

20 

As 

75 

Ba 

137.4 

Bi 

208 

B 

11 

Br 

80 

Cd 

112 

Cs 

133 

Ca 

40 

C 

12 

Ce 

141 

CI 

35.5 

Cr 

52 

Co 

59 

Cb 

94 

Cu 

63.6 

E 

166 

F 

19 

Gd 

156 

Ga 

69 

Ge 

72.3 

Gl 

9 

Au 

197 

He 

2 

H 

1 

In 

113.6 

I 

127 

Ir 

193 

Fe 

56 

La 

138.2 

Pb 

207 

Li 

7 

Mg 

24.3 

Mn 

55 

Hg 

200 

Molybdenum  

Neodymiiim  

Nickel 

Nitrogen 

Osmium 

Oxygen 

Palladium  

Phosphorus 

Platinum  

Potassium  (Kalium). 

Praseodymium  

Rhodium    

Rubidium 

Ruthenium 

Samarium  

Scandium 

Selenium  

Silicon 

Silver  (Argentum) . . . 
Sodium  (Natrium) . . . 

Strontium 

Siilphtir 

Tantalum 

Tellvrii/m 

Terbium  

Thallium 

Thorium  

Tin  (Stannum) 

Titanium 

Tungsten  (Wolfram") 

Uranium 

Vanadium 

Ytterbium 

Yttrium 

Zinc 

Zirconium 


Symbol. 


Mo 

Nd 

Ni 

N 

Os 

O 

Pd 

P 

Pt 

K 

Pr 

Rh 

Eb 

Ru 

Sm 

Sc 

Se 

Si 

Ag 

Na 

Sr 

S 

Ta 

Te 

Tb 

Tl 

Th 

Sn 

Ti 

W 

IT 

V 

Yb 

Y 

Zn 

Zr 


Atomic 
Weight. 


96 
140.5 

58 

14 
191 

16 
106 

31 
194.2 

39.1 
143.5 
103 

85.5 
102 
150 

44 

79 

28 
108 

23 

87.5 

32 
182 
128 

204 
232 
118 

48 
184 
239.8 

51.5 
173 

89 

65.2 

90 


Note.  — The  names  of    metals  are  printed  in  Roman,  non-metals  in 
italics. 


NAMES    AND     FORMULAS 


OF  SOME   OF  THE 


MORE  IMPORTANT  CHEMICAL  COMPOUNDS. 


Acid,  acetic CH3CO.OH. 

"     boric B(OH)3. 

"     hydrochloric  (muriatic) HCl. 

"      hydrocyanic  (pmssic) HCN. 

"     nitric HNO3. 

"     oxalic (CO.OH),. 

"     salicylic C.H.  (OH)CO.OH. 

"     sulphuric H,SO,. 

"     tari^aric C2H.Oj(CO.OH)j. 

Alcohol,  amyl  (fusel  oil) CsHi,OH. 

"        ethyl  (common  alcohol) CaHsOH. 

"        methyl  (wood  alcohol) CH3OH. 

Alum Al™3SO.,K,SO.  +  34HjO. 

Ammonium  hydroxide  (ammonia) NH.OH. 

"  carbonate (NH4)2C03. 

"  chloride NH.Cl. 

nitrate NH.NO3. 

AniUne C«HjNHj. 

Arsenic  trisulphide  (orpiment) AsjS3- 

Arsenious  oxide  (arsenic) A82O3. 

Barium  chloride BaCU. 

"        sulphate BaSO,. 

Benzene  (benzol) CoH». 

Cadmium  iodide Cdl,. 

"  sulphide  (caflmium  yellow) CdS. 

Calcium  carbonate .CaCOj. 

chloride CaCU. 

"        oxide  (lime) CaO. 

sulphate  (gypsum) CaS0.,2H,0. 


NAMES     AND     FORMULAS.  259 

Camphor CioH,oO. 

Carbon  dioxide  (carbonic  acid) CO2. 

"       disulphide CS2. 

"       monoxide CO. 

Chloral  hydrate CCl3COH,HjO. 

Chloroform CHCI3. 

Cobalt  nitrate C02NO3. 

Copper  sulphate  (blue  vitriol) CuSO.iOHaO. 

Ether  (sulphuric  ether) (CaHOaO. 

Perric  chloride  FeaCU. 

Ferrous  sulphate  (green  vitriol) FeSO.jVHjO. 

"       sulphide PeS. 

Glycerin C3H » (0H)3. 

Hydrogen  sulphide  (sulphiiretted  hydrogen) HjS. 

Lead  acetate  (sugar  of  lead) Pb(CH 300.0)3. 

"    chloride PbClj. 

"    chromate  (chrome-yellow) PbCrO,. 

"    oxide  (litharge) PbO. 

"       "       (red  lead) PbaO.. 

Magnesium  chloride MgCU. 

"  oxide  (calcined  magnesia) MgO. 

"  sulphate  (Epsom  salts) MgSCTHzO. 

Manganese  dioxide  (black  oxide  of  Mn) MnOa. 

"  sulphate MnSO,. 

Mercuric  chloride  (corrosive  sublimate) HgClj. 

"        oxide  (red  oxide  of  Hg) HgO. 

"        sulphide  (vermilion) — HgS. 

Mercurous  chloride  (calomel) HgCl. 

Nitro-benzene CeHsNOa. 

Potassium  antimonyl  tartrate  (tartar  emetic) K(SbO)C«H«08,XH20 

"  carbonate  (pearlash) K2CO3. 

"         bicarbonate  (saleratus) KHCO3. 

chlorate KCIO3. 

"  chromate KgCrO,. 

"         bichromate KjCraO/. 

"         ferricyanide KaPeCya. 

"         ferrocyanide  (prussiate  of  iwtash) KiPeC^Jy,. 

"         hydroxide  (caustic  potash) KOH. 

«         iodide KI. 


260 


NAMES     AND     FORMULAS. 


Potassium  nitrate  (niter,  saltpeter) ElNOa. 

"  permanganate KMnO,. 

"         bitartrate  (cream  of  tartar) KHC.H.O,. 

Silver  nitrate  (lunar  caustic) AgNO^ . 

Sodium  pyroborato  (borax) Na2B4O7,10H2O. 

"       carbonate  (soda) NajCOa. 

"       chloride  (common  salt) NaCl. 

"       hydroxide  (caustic  soda) NaOH. 

"       sulphate  (Glauber's  salt) NajSClOHoO. 

"       potassium  tartrate  ("Rochelle  salt) NaKC.H.O„,4H20. 

Stannic  sulphide  (mosaic  gold) SnSj. 

Strontium  nitrate Sr2N03 

Sugar,  cane CisHjsOu. 

"      grape  (glucose) CuHijOo. 

Turpentine CioH,e. 

Zinc  sulphate ZuSO«. 


Directions  for  Experiments. 

The  following  simple  suggestions  will  enable  any  student  to  perform  all 
the  experiments  mentioned  in  this  work.  Many  easy  illustrations  are  also 
given  in  addition  to  those  named  in  the  text.  Carefully  compare  them 
with  tliose  contained  in  the  body  of  the  book.  The  full-faced  figures 
refer  to  the  pages  of  the  book,  and  the  light-faced  figures  to  the  number 
of  the  experiment. 

INORGANIC     CHEMISTRY. 

I .  Inilestruetibilitij  of  Sfntter.— Two  invisible  substances  are  formed 
by  the  burning  candle,  as  may  be  proved  by  the  following  experiments : 

1.  Hold  a  cool,  dry  tumbler,  or  glass  flask,  over  a  candle-flame.  The  glass 
will  be  immediately  covered  with  a  fine  dew  from  the  steam  produced  by 
the  burning  candle. 

2.  Lower  a  lighted  candle-end,  fixed  on  a  handle  of  wire,  into  a  clean 
glass  bottle,  and  loosely  cover  the  mouth  of  the  bottle  with  a  piece  of 
paper.  After  the  flame  has  gone  out,  remove  the  candle ;  pour  a  little  clear 
lime-water  (see  p.  139)  into  the  bottle,  and  shake.  The  lime-water  becomes 
milky,  while  in  another  bottle  in  which  no  candle  has  been  burned  it  will 
remain  clear  (prove  this).  This  shows  that  the  burning  candle  has  formed 
an  invisible  substance,  which,  unlike  air,  can  render  lime-water  turbid. 

Weight  tind  Itnpenet rabllity  of  Gases. — 3.  Weigh  a  flask  or  bottle  full 
of  air,  and  again  after  the  air  has  been  exhausted  by  means  of  an  air- 
pump.    Willie  on  the  balance,  allow  the  air  to  enter  again. 

4.  Balance  a  bottle  full  of  air,  and  then  fill  it  with  carbon  dioxide  (see 
p.  06). 

5.  The  impenetrability  of  air  may  be  shown  by  plunging  a  tumbler, 
mouth  downward,  into  water.  The  water  rises  but  a  short  distance  into  the 
tumbler.  . 

3.  Chetnic(tl  Action,  of  Li(/ht. — 6.  Dissolve  a  little  salt  and  a  little 
silver  nitrate  in  separate  portions  of  water.  On  mixing  the  solutions,  a 
white  precipitate  is  formed,  which,  on  exposure  to  sunlight,  turns  dark. 

Effect  of  Solution  in  I'ronioting  Chemical  Action. — 7.  The  sodium 
carbonate  and  tartaric  acid  may  be  intimately  mixed  by  grinding  them 
together  in  a  mortar.  No  chemical  action  will  take  place  till  water  is 
added. 

I  I  .  Oxygen.— 8.  Heat  4-5  grams  of  red  oxide  of  mercury  in  a  hard 
glass  tube,  sealed  at  one  end.  Mercury  is  deposited  on  the  sides  of  the  tube 
beyond  the  flame,  and  a  gas  is  given  off  which  may  be  proved  to  be  O  by 
its  kindling  a  match  on  which  a  spark  has  been  left.  By  continuing  the 
experiment,  all  of  the  HgO  can  be  converted  into  Hg  and  O. 


262  DIRECTIONS     FOR     EXPERIMENTS. 

0.  Put  into  a  dry  test-tube  a  few  grams  of  pure  potassium  chlorate,  and 
heat  cautiously.  The  test-tube  may  be  supported  by  a  strip  of  thick  pai)er 
twisted  around  it  at  the  top.  Move  the  tube  to  and  fro  through  the  llanic  at 
first,  until  it  becomes  fully  heated ;  keep  the  tube  inclined,  and  not  perpen- 
dicular, letting  the  flame  strike  the  side  rather  than  the  bottom.  Hold  the 
thumb  lightly  over  the  mouth  of  the  tube.  The  salt  melts  quietly,  and  then 
begins  to  decompose,  with  the  appearance  of  boiling.  That  O  is  given  off  is 
proved  as  in  Ex.  8.  "When  no  more  gas  is  evolved,  allow  the  salt  to  cool, 
shaking  it  gently  to  prevent  its  attaching  itself  to  the  tube.  The  residue  is 
no  longer  a  chlorate,  and  gives  out  no  yellow  gas  if  moistened  with  HoSO^, 
but  will  yield  a  white  precipitate  witli  AgNOa,  which  shows  it  to  be  a  chloride. 

10.  Most  of  the  following  experiments  may  be  performed  in  test-tubes  as 
above,  but,  when  it  is  desirable  to  make  a  larger  quantity  of  O,  one  ounce 
of  j)otassium  chlorate  is  very  carefully  pulverized,  and  mixed  with  half  that 
quantity  of  black  oxide  of  manganese.*  Be  careful  not  to  grind  them  to- 
gether. The  mixing  is  effected  by  placing  them  both  on  sheets  of  clean 
paper,  and  pouring  them  back  and  forth  from  one  sheet  to  the  other  until 
the  mixtui'e  has  a  uniform  gray  color.  Place  the  mixture  in  a  flask ;  fit  a 
cork  to  the  nozzle ;  then  withdraw  the  cork,  and  with  a  round  file  bore  a 
hole  through  it  just  large  enough  to  admit  a  glass  tube  bentt  as  shown  in 
Fig.  1.  Return  the  cork  and  tube,  arrange  the  apparatus  as  shown  in  the 
figure,  and  apply  the  heat.  This  must  be  done  very  cautiously  at  first,  hold- 
ing the  lamp  in  the  hand,  and  moving  it  around  so  that  the  flame  may 
strike  all  the  lower  part  of  the  flask,  and  thus  expand  it  uniformly.  Be 
careful,  also,  that  no  draft  of  cold  air  strikes  against  the  heated  glass.  Tlie 
first  few  bubbles  of  gas  will  consist  mainly  of  the  air  contained  in  the  flask, 
and  should  not  be  caught.  When  the  gas  begins  to  pass  over  freely, 
diminish  the  heat.  When  tJie  gas  ceases,  remove  the  stopper  from  the  flask,  or  lift 
the  end  of  the  tube  out  of  the  water ;  otherwise,  as  the  flask  cools,  the  water  in 
the  tube  will  rush  back  into  the  flask,  and  break  it.  AVlien  the  retort  is  nearly 
cool,  pour  in  some  warm  water  to  dissolve  the  residuum,  which  may  then 
be  poured  out,  and  the  flask  dried  for  future  use. 

Instead  of  bending  the  glass  tubing,  it  may  bo  cut  into  short  lengths, 
and  the  pieces  joined  by  bits  of  rubbei-  tubing.  The  advantage  of  this  is 
that  the  flexible  joints  are  not  liable  to  break,  and  the  apparatiis  may  be 
more  easily  moved.    Where   a  large  quantity  of  O  is  to  be  made,  a  copper 


*  In  order  to  tost  the  purity  of  the  materials,  and  thus  avoid  any  danger  of  an  ex- 
plosion, it  is  well,  previous  to  putting  the  nii.xture  in  the  flask,  to  place  a  little  in  an 
iron  spoon,  and  heat  it  over  the  lamp.  If  the  gas  pass  off  quietly,  no  danger  need  be 
apprehended. 

+  A  glass  tube  may  be  bent  at  any  point  by  softening  that  part  in  the  flame  of 
an  ordinary  gas-burner.  Practice  alone  will  give  the  required  exiicrtness.  The  fol- 
lowing points  should  be  observed  :  1.  Keep  the  tube  slowly  turning  between  the 
fingers,  so  that  it  may  be  equally  heated  on  all  sides  ;  2.  Do  not  twist  or  pull  the  tube 
while  heating  ;  3.  Do  not  bend  it  until  very  soft  ;  if  not  hot  enough,  the  elbow  will 
be  flattened.  Blowing  gently  into  the  tube  at  the  moment  of  bending  also  preTeute 
flattening. 


DIRECTIONS     FOR     EXPERIMENTS.  263 

retort  and  rubber  tubing  wiU  be  found  cheap  and  convenient.  No  especial 
care  is  then  needed  in  managing  the  heat.* — In  place  of  the  pneumatic 
tub,  a  pail  or  a  tin  pan  may  be  used,  letting  the  bottle  rest  on  a  shelf,  as 
in  Fig.  8,  or  on  a  couple  of  bricks. — The  bottles  for  collecting  the  gas  may 
be  the  regular  "deflagrating  jar"  of  the  chemist,  or  the  common  "packing 
bottle  "  of  the  druggist.  They  are  to  be  sunk  in  the  water  of  the  pneumatic 
tub,  and  filled ;  then  inverted,  and  lifted  upon  the  shelf,  carefully  keeping 
the  lower  edge  of  the  bottle  under  the  water.  The  bottles  may  also  be  filled 
from  a  pitcher,  then  closed  with  the  hand  or  a  plate,  and  quickly  inverted 
and  placed  on  the  shelf  in  the  tub  or  pan  ready  for  xtse.  As  soon  as  a 
bottle  is  filled  with  gas,  a  plate  may  be  slipped  under  the  mouth,  and  thvis, 
leaving  enough  water  in  the  plate  to  cover  the  lower  edge,  be  set  aside,  as 
in  Fig.  1.  Gas  may  be  passed  from  one  jar  to  another  in  the  manner 
shown  in  Fig.  18. — AVhile  the  gas  is  being  collected,  the  water  from  the 
bottles  which  are  filling  may  cause  the  tub  to  overrun ;  to  prevent  this, 
arrange  a  siphon  to  carry  off  the  water  into  a  pail  below  the  table. — ^When 
a  jar  of  gas  is  wanted  for  use,  slip  a  plate  under  the  mouth,  or  simply  close 
it  with  the  hand,  and,  lifting  the  jar  out,  carry  it  to  the  table,  and  place  it 
mouth  upward.  TTncover  only  when  the  experiment  is  ready  to  be  per- 
formed, as  the  gas  will  slowly  diffuse. 

I  3.— H-  The  experiment  with  the  candle  may  be  very  strikingly  per- 
formed by  filling  a  common  fruit^jar  with  O,  and  another  with  N.  The 
covers  may  be  loosely  laid  on  top,  and  the  lighted  candle  passed  quickly 
from  one  to  the  other,  as  mentioned  in  note  on  page  30.  The  candle 
may  be  simply  stuck  on  the  end  of  a  bent  wire,  as  in  Fig.  15,  but  it  is  much 
neater  to  have  the  tinsmith  fit  a  little  cup  for  its  reception. 

I  4. — 12.  If  brimstone  be  used  in  the  experiment  with  S,  and  it  fails  to 
light  readily,  pour  upon  it  a  few  drops  of  alcohol,  and  then  ignite. 

13.  Worn-out  watch-springs  can  be  obtained  gratis  of  any  jeweler,  and 
may  be  easily  straightened  by  slightly  heating,  and  then  drawing  them  be- 
tween the  fingers.  If  the  end  of  each  spring  be  strongly  heated,  and  then 
pounded  with  a  hammer  on  any  smooth,  hard  stirface,  the  temper  may  be 
drawn,  and  the  edge  sharpened.  Make  a  slit  with  a  knife  in  the  side  of  a 
match,  into  which  insert  the  edge  of  the  spring.  Take  a  piece  of  zinc  or  tin 
large  enough  to  cover  the  mouth  of  the  jar  containing  the  O,  and  make  a 
hole  through  it  with  a  nail.  Pass  the  other  end  of  the  spring  through  this 
hole,  and  then  through  a  thin  cork.  The  spring  is  now  ready  for  burning. 
The  metal  cover  will  prevent  the  flame  from  coming  out  of  the  jar  and 
burning  one's  hand,  and  the  cork  will  hold  the  spring  in  its  placet    When 


*  If,  during  the  operation,  the  gas  suddenly  ceases  to  come  off,  remove  the  flame,  and 
ascertain  whether  the  delivery-tube  is  not  choked  up,  which  would  result  in  a  very  violent 
explosion  of  the  retort. 

t  It  is  well  to  obtain  several  pieces  of  thin  board  or  shingles,  about  six  inches  square, 
bore  a  small  hole  in  the  center,  and  insert  a  match  end  or  small  plug.  These  may  be 
used  as  covers  in  most  experiments  where  a  deflagrating  spoon  is  to  be  employed.  The 
handle  of  the  spoon  is  passed  through  this  hole,  and  held  in  place  by  the  small  plug. 


264  DIRECTIONS     FOR     EXPERIMENTS. 

the  match  is  ignited,  and  then  lowered  into  the  jar  of  O,  the  spring  should 
not  reach  more  than  half-way  to  the  bottom,  and  should  toe  piiahed  down 
as  it  burns.  A  cheap  packing  bottle  should  be  used,  as  the  gl;uss  is 
frequently  broken  by  the  melted  globules  of  iron.  Do  not  All  it  quite  full  of 
gas,  as  then,  on  inverting,  a  little  water  will  be  left  at  the  bottom,  or  some 
fine  sand  may  be  thrown  into  the  jar  before  the  experiment.  The  illustra- 
tion may  be  repeated  with  a  coil  of  fine  iron  wire.  The  springs  from  an 
old  hoop-skirt  burn  nicely  in  O. 

14.  When  S,  P,  cliarcoal,  a  wax  candle,  Na,  and  other  substances  are 
to  be  burned  in  O,  they  may  be  supported  on  the  end  of  pieces  of  glass 
tube  bent  like  the  letter  J,  and  left  open  at  the  shorter  end  only.  For  this 
purpose,  covei-s  must  be  provided  with  holes  large  enough  for  the  glass 
tube  to  pass  through.  Or  a  "  deflagrating  spoon "  may  be  readily  extem- 
porized to  contain  the  phosphorus.  Hollow  a  small  piece  of  chalk,  and  at- 
tach a  wire  to  it,  which  may  then  be  secured  to  a  metal  top,  as  in  the  case 
of  the  watch-spring.  This  need  not  be  pushed  down  into  the  jar  as  the 
burning  progresses.  Be  careful  to  cut  the  phosphorus  under  water,  to  dry 
it  carefully  with  blotting-paper,  and  ncjt  to  handle  it.  The  fumes  are  very 
disagreeable,  and  should  not  be  inhaled  or  allowed  to  escape  into  the  room. 
They  soon  dissolve  when  shaken  with  a  little  water. 

I  5.— 15-  In  burning  bark  charcoal  in  O,  force  the  gas  into  the  bottle 
through  a  bit  of  rubber  tubing  at  the  mouth.  By  placing  this  at  one  side, 
the  gas  is  given  a  rotary  motion,  and  the  sparks  of  ignited  charcoal  will 
drive  around  the  bottle  in  a  beautiful  maelstrom  of  fire.  The  gas  may  be 
forced  in  fr6m  a  rubber  bag,  and  this  striking  effect  easily  produced. 

16.  Arrange  a  receiver  upon  the  bed-plate  of  the  air-piimp  so  that  O 
may  be  admitted  from  a  gas-bag  by  turning  a  stop-cock.  Put  under  the  re- 
ceiver an  ignited  tallow  candle,  with  a  big  wick.  Exhaust  the  air  until  the 
flame  goes  out,  and  there  is  left  only  a  coal  of  fire.  Admit  the  air,  and  it 
will  have  no  effect  to  restore  the  blaze.  Force  in  some  O  quickly,  and  the 
coal  will  burst  instantly  into  a  brilliant  white  light,  brighter  than  at  the 
first. 

17.  The  oxidation  of  one  solid  by  means  of  nascent  O,  liberated  from 
another  solid,  can  be  shown  as  follows ;  Heat  about  five  gi-anis  of  potassium 
nitrate  (saltpeter)  in  a  test-tube  until  it  melts  quietly.  Remove  the  lamp, 
and  throw  in  pieces  of  S  as  large  as  peas,  when  they  burn  with  an  intensely 
bright  flame.  The  heat  is  often  sufficient  to  melt  the  glass,  and  the  pre- 
caution should  be  taken  to  hold  it  over  an  iron  plate  or  sand-bath.  Or  melt 
a  quarter  of  a  pound  of  saltpeter  in  an  evaporating  dish ;  an  ordinary  tin 
cup  will  answer.  Put  it  on  some  burning  coals  in  a  draught  to  caiTy  off 
the  fumes.  Plunge  into  the  liquid  a  piece  of  bark -charcoal,  strongly  ignited. 
The  oxygen  of  the  saltpeter  will  support  the  combustion,  and  the  charcoal 
will  deflagrate  in  a  rushing  volcano  of  scintillations. 

23.  Ozone.— 18.  Scrape  off  the  white  coating  of  a  stick  of  phosphorus 
under  water.  Place  it  in  a  wide-mouth  liter-bottle  full  of  air,  with  about  a 
teaspoonful  of  water  at  the  bottom.  Close  the  mouth  of  the  bottle  with 
a  glass  plate,  and  expose  the  whole  for  an  hour  or  two  to  a  temperature  of 


DIRECTIONS     FOR     EXPERIMENTS.  265 

15°  or  20°  C.  Then  invert  the  neck  of  the  bfcttle  in  water,  and  allow  the  phos- 
phorus to  fall  out.  Replace  the  glass  plate,  and  withdraw  the  bottle  and  its  con- 
tents from  the  water.  The  phosphorus  in  this  experiment  undergoes  a  slow  ox- 
idation, during  wliich  a  little  ozone  is  formed,  and  is  left  mixed  with  the  air ; 
but  the  ozone  wiU  be  again  destroyed  if  it  is  left  too  long  with  the  phosphorus. 

19.  Put  in  an  evaporating  dish  a  little  starch ;  cover  it  with  water  in 
which  a  few  crystals  of  potassium  iodide  have  been  dissolved,  and  heat. 
Stir  the  liquid,  to  prevent  lumps.  When  cooked,  immerse  in  the  paste  slips 
of  white  blotting  or  clean  writing-paper,  and  hang  them  up  to  dry.  They 
must  be  moistened  when  used. 

20.  Let  some  ozone  pass  into  a  clean  bottle  containing  a  little  pure 
mercury.  Shake  the  whole  very  carefully.  The  metal  will  change  so  as  to 
act  like  an  amalgam  of  tin  and  mercury,  and  will  form  a  mirror  on  the 
sides  of  the  bottle. 

28.  Nitro<jen.—21.  The  phosphorus  will,  without  the  aid  of  heat, 
gradually  remove  the  O  from  the  air,  forming  phosphorus  trioxide 
(P2O3),  which  will  be  dissolved  by  the  water,  and  in  a  day  or  two  the 
gas  which  is  left  will  be  nearly  pure  N.  To  show  the  proportion  of  O  and 
of  N  in  common  air :  Take  a  long  glass  tube ;  seal  one  end  air-tight ;  with 
a  camel's-hair  brush  and  black  paint  mark  upon  the  outside  the  division 
into  fifths,  and  introduce  a  bit  of  phosphorus  on  the  end  of  a  long  wire. 
Place  the  tube  upright,  with  its  open  end  under  water.  The  water  will 
gradually  rise  in  the  tube  unto,  it  fills  one  fifth  of  the  tube. 

3  I  . — 22.  For  making  HNO3,  take  equal  weights  of  sodium  or  potassium 
nitrate  and  strong  sulphuric  acid.  The  fumes  may  be  caught  in  an 
evolution-flask,  which  is  kept  cool  by  water.  When  the  retort  is  partially 
cooled,  at  the  conclusion  of  the  process,  pour  in  a  little  warm  water,  to  dis- 
solve the  potassium  sulphate,  otherwise  the  retort  may  break  by  the  crystal- 
lization of  the  salt. 

23.  To  show  the  effect  of  HNO3  upon  the  metals,  procure  bits  of  tin 
and  copper  from  the  tinsmith.  Take  six  wine-glasses,  and  place  them  in  a 
row  upon  ordinary  soup-plates  containing  a  little  water.  Cover  each  with 
a  beaker-glass  or  bell-jar.  In  one  put  a  strip  of  copper,  in  another  a  little 
mercury,  in  another  a  piece  of  pure  tin  (not  tinned  iron),  in  another  a  strip 
of  zinc,  in  another  a  new  iron  nail,  in  the  last  a  bit  of  platinum  wire  or 
foil.  Pour  strong  nitric  acid  upon  each,  and  cover  immediately.  The  copper, 
mercury,  and  zinc  dissolve  with  a  violent  evolution  of  gas.  The  tin  is  oxid- 
ized to  a  white  powder,  while  the  iron  and  platinum  are  unaffected.  Touch 
the  iron  with  a  piece  of  zinc,  and  it  begins  to  dissolve.  Put  another  new 
nail  in  dilute  nitric  acid,  and  it  is  rapidly  dissolved. 

24.  Mix  slowly  together  one  ounce  oil  of  vitriol  and  two  ounces  of  the 
strongest  nitric  acid.  When  cold,  dip  paper  into  the  mixture,  and  quickly 
wash  with  cold  water  and  dry.  The  paper  will  burn  with  a  flash  like  gun- 
powder. To  avoid  getting  the  acid  on  the  hands,  use  glass  tubes  or  rods 
for  taking  the  paper  out  of  the  acid.  Cotton  treated  in  the  same  way  be- 
comes soluble  in  a  mixture  of  alcohol  and  ether,  and  is  used  by  photog- 
raphers in  making  collodion. 


266  DIRECTIONS     FOK     EXPERIMENTS. 

33.-25.  A  special  apparatus  is  necessary  both  for  preparing  and  in- 
haling nitrous  .oxide  safely.  This  consists  of  a  gla.ss  retort— as  shown  in 
the  cut-a  wash-bottle,  and,  in  addition,  a  gas-bag  of  fi-oni  twenty  to  fifty 
gallons  capacity  for  storing  the  gas,  and  a  smaller  bag  of  from  three  to  five 
gallons,  with  a  wide,  wooden  mouth-piece  for  inhalation.  It  is  well  to  pass 
the  gas  through  a  large  wash-bottle  half  full  of  caustic  potash  solution, 
and  a  second  half  full  of  HjO,  as  shown  in  Fig.  13,  thence  by  a  rubber  tube 
directly  into  the  large  gas-bag.  The  utmost  care  should  be  taken  both  in 
preparing  and  administering  this  gas,  as  other  oxides  of  nitrogen  are  liable 
to  be  present,  especially  if  too  high  a  heat  is  used.  Before  preparing  the 
gas,  pour  into  the  bag  a  couple  of  gallons  of  II^O,  by  standing  over  which 
it  will  be  purified  in  a  few  hours.  When  about  to  administer  the  gas, 
let  the  subject  grasp  his  nose  firmly  between  his  thumb  and  forefinger; 
then,  inserting  the  wooden  mouth-piece,  be  careful  that  he  does  not  inhale 
any  of  the  external  air,  but  takes  full,  deep  breaths  in  and  oxit  of  the  gas- 
bag. Watch  the  eye  of  the  subject,  and  notice  the  influence  of  the  gas. 
Great  care  is  necessary,  and  no  one  sliould  ever  inhale  the  gas  who  is  not 
in  good  health,  who  is  troubled  witli  a  rush  of  blood  to  the  head,  any  lung 
or  heart  disease,  or  is  of  a  plethoric  habit.  N^O  should  never  be  admin- 
istered except  when  prepared  and  given  by  an  experienced  person. 

Repeat  experiments  11,  12,  and  13  with  this  gas. 

26.  Half  fill  a  test-tube  with  gas,  over  water.  Close  the  tube  under 
water  firmly  with  the  thumb,  and  then  agitate  the  water  and  gas  together. 
On  removing  the  tliumb  under  water,  a  considerable  rush  of  water  into  the 
tube  will  occur,  as  the  gas  is  soluble  in  about  its  own  volume  of  cold  water. 
By  this  circumstance  the  gas  is  easily  distinguished  from  O. 

34.-27.  When  a  jar  is  filled  with  the  NO,  it  may  be  lifted  out  of  the 
II 2O  and  inverted,  when  the  NOj  will  pass  ofl:  in  red  clouds.  If  the  jar  be  left 
in  the  cistern,  and  one  edge  be  lifted  so  as  to  admit  a  bubble  of  air,  red 
fumes  will  fill  the  jar.  By  standing  a  moment,  the  water  will  absorb  tlie 
red  vapor.  The  process  may  be  repeated  several  times  with  the  remaining 
gas.  The  variation  of  this  experiment,  described  in  the  note  on  page  34, 
will  be  found  very  interesting.  The  change  of  color  produced  by  mixing 
nitric  oxide  with  any  gas  containing  free  O,  often  affords  a  convenient 
means  of  detecting  small  quantities  of  O  when  present  in  admixture  with 
other  gases,  such,  for  instance,  as  coaJ-gas.  ITence  NO  may  be  used  to  dis- 
tinguish between  O  and  N^O. 

28.  Into  a  large  jar  inverted  over  water,  introduce  a  measured  quantity 
of  NOv  and  exactly  half  as  much  p\ire  O.  The  two  combine  to  form  NO», 
which  is  soon  dissolved  in  the  water,  and  disappears.  This  illustrates  Gay 
Ijussac's  law  that  gases  combine  in  simple  proportions  by  volume. 

35. — Ammonia  is  so  much  lighter  than  air,  that  it  may  be  conveniently 
collected  by  upward  displacement,  as  shown  in  Pig.  10. 

36.-29.  If  the  bottle  used  for  collecting  the  NH3  be  removed,  and  the 
flame  of  a  Bunsen  burner  be  applied  to  the  jet  of  issuing  gas,  the  NH.,  will 
not  burn,  but  the  gas-flame  will  be  tinged  with  a  pale  yellow  color.  To 
show  the  burning  of  NH3  in  O,  lead  O  into  a  wide-mouthed  flask  contain- 


DIRECTION'S     FOR     EXPERIMENTS. 


267 


ing  strong  aqua  ammonia  (Fig.   12).     On  gently  heating,  the   ammonia, 
mixed  with  O,  will  come  off,  and  may  be  lighted  at  the  mouth  of  the  flask. 

39.  J{y(lrof/cu.—30.  For  preparing  H,  the  apparatus  shown  in  Fig.  13 
is  very  convenient.  The  wash-bottle,  d,  is  necessary  only  when  it  is  desired 
to  purify  the  gas  for  inhaling.  A  common  junk-bottle,  fitted  with  a  cork 
and  a  glass  tube,  will  answer  for  all  ordinary  experiments,  but  a  "hydro- 
gen generator,"  as  described  below,  is  much  more  satisfactory.  The  Zn  for 
making  H  should  be  granvilated.*  "Water  may  be  poured  into  the  flask 
until  the  lower  end  of  the  funnel  is  covered,  before  adding  the  acid.  The 
flow  of  gas  may  be  regulated  by  additions  of  acid,  as  may  be  wanted.  One 
part  of  acid  to  ten  or  twelve  parts  of  water  will  liberate  the  gaa  rapidly. 
If  too  much  HjSO,  be  added,  the  liquid  is  apt  to  froth  over. 

A  constant  hydrogen  generator  can  be  readily  made  by  taking  two 
bottles  with  tubulature  near 
the  bottom,  such  as  are  sold 
by  druggists  for  the  "nasal 
d  o  u  c  h  e,"  and  connecting 
them  with  a  strong  rubber 
tube.  One  is  fitted  with  a 
cork  and  delivery  tube  pro- 
vided with  a  stop-cock.  In 
this  bottle  is  placed  a  layer 
of  pebbles  or  broken  glass, 
and  upon  this  a  quantity  of 
zinc  scraps.  In  the  other 
bottle  is  dilute  H^SO..  On 
opening  the  stop-cock,  the 
acid  comes  in  contact  with 
the  zinc,  and  H  is  evolved. 
As  soon  as  the  stop-cock  is 
closed,    the    pressure   of   the 

gas  drives  the  acid  back  into  the  other  bottle.    The  same  kind  of  apparatus 
may  be  employed  for  generating  CO™  or  HoS. 

A  hydrogen  generator,  similar  in  principle  to  the  Dobereiner  lamp 
(Fig.  19),  can  be  made  by  cutting  off  the  bottom  of  a  tall  and  narrow  bottle, 
filling  it  with  zinc  scraps,  and  closing  at  the  lower  end  with  a  perforated 
rubber  cork,  and  at  the  upper  end  with  a  perforated  cork  carrying  a  brass 
or  glass  tube  and  stop-cock.  Place  it  upright  in  a  jar  of  dilute  sulphuric 
acid. 

In  experimenting  with  H,  great  care  must  be  used  not  to  ignite  the  jet 
of  gas  until  all  the  common  air  has  passed  out  of  the  flask ;  otherwise  a 
severe   explosion   will  ensue.t    It  is  a  safe  precaution  to  test  the  gas  by 


*  This  is  easily  done  by  melting'  the  Zn  in  an  iron  ladle,  and  pouring  the  metal 
slowly  from  a  little  height  into  a  basin  of  water. 

t  Always  wrap  a  cloth  around  the  U  generator  when  you  ignite  the  gas,  as  an 
additional  precaution. 


268  DIRECTIONS     FOR     EXPERIMENTS. 

passing  it  in  bubbles  up  through  HjO,  and  igniting  them  at  the  surface ; 
the  force  of  the  combustion  will  indicate  if  there  be  any  danger.  H  must 
not  be  kept  in  bags  for  any  great  length  of  time,  as  the  air  will  gradually 
force  itself  in,  and  the  gas  will  partly  pass  out,  thus  forming  an  explosive 
mixture  which  it  is  dangerous  to  ignite. 

31.  The  gases  may  be  mixed  in  the  following  manner :  Fit  a  good  cork 
into  the  neck  of  a  large  jar,  and  pass  through  it  a  tube  five  centimeters 
long.  Bind  a  short  piece  of  rubber  tubing  firmly  to  the  tube,  and  close  this 
elastic  tube  with  a  small  pinch-cock.*  Fill  the  jar  with  water  over  the 
pneumatic  tub.  Fill  a  small  jar,  which  will  hold  about  half  a  liter,  with  O, 
and  transfer  it,  as  shown  in  Fig.  18,  to  the  large  jar.  Fill  the  same  jar 
with  H,  and  transfer  it  to  the  large  jar.  Repeat  the  operation  with  the  H, 
so  as  to  obtain  in  the  larger  jar  a  mixture  of  half  a  liter  of  O  and  one  liter 
of  H.  Having  previously  softened  a  thin  bladder  by  soaking  it  in  water, 
tie  into  the  neck  of  it  a  glass  tube  five  centimeters  long;  then  adjust  to 
the  projecting  portion  a  piece  of  rubber  tubing  provided  with  another 
pinch-cock.  Press  the  air  out  of  the  bladder;  connect  the  two  pieces  of 
rubber  tube  by  means  of  a  short  piece  of  glass  tubing;  depress  the  jar  in 
the  pneumatic  tub,  and  then  open  each  pinch-cock.  The  gas  will  now  pass 
into  the  bladder,— if  it  does  not,  press  the  jar  deeper  into  the  water.  Close 
both  pinch-cocks,  and  remove  the  bladder.  Now  place  the  end  of  the  tube 
attached  to  the  bladder  under  some  soaivsuds,  and  blow  a  mass  of  soap- 
bubbles  by  squeezing  the  bladder.  Remove  the  bladder  to  a  distance,  and 
then  apply  a  light  to  the  bubbles.  A  loud  explosion  will  immediately 
follow. 

3S.  A  clay  tobacco-pipe  may  be  attached  to  the  gas-bag  by  means  of  a 
bit  of  rubber  tubing.  Dip  the  pipe-bowl  into  the  soap-suds,  and,  lifting  it 
out,  blow  a  bubble  with  the  mixed  gases,  and  then  detach  it  by  a  quick 
motion.  When  the  gas-bag  is  removed,  ignite  the  biibble,  which  will  ex- 
plode sharply.  If  bubbles  be  blown  with  H  alone,  they  will  rapidlj'  rise, 
and,  if  out-of-doors,  will  float  to  a  great  distance. t 

33.  H  is  the  lightest  known  sul)stance.  FiU  two  bottles  with  the  gas, 
suspend  one  inverted  from  the  ring  of  the  retort-holder,  and  place  the 
other  right  side  up  on  the  table.  In  a  few  minutes  the  upright  cylinder 
will  be  found  to  contain  little  or  no  H,  while  the  inverted  bottle  is  nearly 
full. 

34.  Suspend  an  inverted  beaker  glass  from  the  end  of  the  scale  beam 
(Fig.  27).  Balance  it  carefully;  then  fill  it  with  H  gas.  It  will  be  found 
much  lighter  than  before. 

35.  Take  a  small  porous  cup,  such  as  is  used  for  electrical  batteries.  Fit 
a  cork  to  it,  and  pass  a  long  glass  tube  through  the  cork.    Cover  the  cork 

*  Small  i)inch-cock8  are  sold  for  this  purpose.  Thuy  are  clieaiwr  than  stop-cocke,  and 
ansuor  every  purpos-e.    In  lieu  of  these,  common  sprin>;  clothes-pins  may  be  used. 

t  If  one  has  a  large  rubber  gas-bag,  with  stop-cock  and  rubber  tubing,  and  a  glass 
receiver  fitted  with  a  stop-cock  on  top,  these  may  be  attached,  and  the  gases  measured  in 
the  receiver,  and  then  passed  directly  into  the  bag.  Such  apparatus,  though  convenient, 
iB  not  necessaiy  to  illustrate  the  properties  of  the  gaees. 


DIRECTIONS     FOR     EXPERIMENTS. 


269 


with,  plaster  of  Paris.  Place  the  tube  upright,  with  its  lower  end  dipping 
into  a  colored  liquid  (CuSO,  +  NH4OH).  Hold  a  jar  of  H  over  the  porous 
cup.  The  H  enters  the  cup,  driving  the  air  out  of  the  lower  end  of  the 
tube.  Remove  the  jar,  and  the  liquid  will  rise  several  inches  in  the  tube. 
(See  "  Physics,"  p.  50.) 

36.  A  substitute  for  spongy  platinum  in  the  experiments  with  hydrogen 
gas :  Make  a  cylinder  of  pumice-stone,  three  eighths  of  an  inch  in 
diameter.  With,  a  fine  saw,  cut  it  into  disks  about  one  twentieth  of  an 
inch  thick.  Soak  these  for  some  time  in  a  strong  solution  of  bichloride  of 
platinum  in  alcohol,  and  then  as  long  in  an  alcoholic  solution  of  sal- 
ammoniac.  After  being  once  thoroughly  ignited,  these  disks  will  inflame  a 
jet  of  hydrogen. 

45.-37.  The  analysis  of  water  can  be  readily  performed  as  follows: 
Take  a  wide  bottle  (the  height  is  unimportant),  and  cut  it  off  about  two 
and  one  half  inches  below  the  neck,  by  making  a  scratch  with  a  three- 
cornered  file,  and  then  applying  near  the  scratch  a  very  hot  piece  of  wire  or 
glass,  or  a  small  blow-pipe  flame.  The  crack  will  follow  the  flame  slowly 
around  the  bottle.  Take  two  strips  of  platinum  foil,  and  put  one  on  each 
side  of  a  well-fitting  cork,  so  that  one  end  extends  into  the  bottle,  the  other 
outside  of  the  neck.  Support  the  apparatus  inverted  upon  a  ring  of  the  re- 
tort stand,  and  fill  nearly  full  of  water  acidulated  with  H5SO4.  Connect 
the  strips  of  Pt  with  the  poles  of  a  battery  of  two  bichromate  or  Bunsen 
cells.  Bubbles  of  gas  at  once  appear,  and  can  be  collected  in  inverted 
test-tubes,  and  tested.  Instead  of  a  bottle-neck,  a  broken  funnel  may  be 
employed.     (See  "  Physics,"  p.  237.) 

38.  The  synthesis  of  water  may  be  shown,  and  also  its  composition  by 
weight,  by  passing  dry  H  over  dry  CuO.    The  CuO  is  placed  in  a  bulb-tube 


of  hard  glass  C\  and  weighed.  The  tube  D,  filled  with  pieces  of  fused  cal- 
cium chloride,  is  also  weighed.  The  H  generated  in  A  is  dried  by  CaClo  at 
-B,  and  passes  over  the  CuO  at  C.  "When  the  air  has  all  been  expelled,  heat 
the  CuO  until  it  has  a  bright  red  color.  Allow  the  H  to  pass  through  until 
the  tube   C  is  cold.    Take  the  apparatus  apart,  and  weigh  the  tube  C;  it 


270 


DIRECTIONS     FOR     EXPERIMENTS. 


39.  Burning    H 


O. 


will  have  decreased  in  weight  by  a  quantity  equal  to  that  of  the  O  expelled. 
Weigh  the  tube  D.  It  has  increased  by  a  quantity  equal  to  that  of  the 
water  formed.  If  6'  has  lost  16  grams  in  weight,  D  will  have  increased  18 
grams  in  weight,  showing  that  16  parts  of  O  wiU  form  18  parts  of  water, 
by  taking  up  2  parts  of  H. 

Attach  a  CaClj  drying  tube  to  a  hydrogen 
generator,  and  to  this  a  glass  tube  bent  twice 
at  right  angles,  and  then  turned  up  at  the  end, 
as  shown  in  the  figure.  Take  a  small  piece  of 
Pt  foil,  and  roU  it  around  a  darning-needle  so 
as  to  form  a  smaU  tube.  Soften  the  end  of  the 
glass  tube,  and  slip  this  little  tube  into  it  while 
hot,  then  hold  them  in  the  flame  until  the  glass 
settles  down  against  the  Pt  on  all  sides.  When 
the  air  has  all  been  expelled 
from  the  generator,  throw  a 
towel  over  it,  and  ignite  the 
H,  then  bring  it  into  a 
broad  jar  of  O.  The  heat  is 
very  intense,  hence  the  need 
of  a  Pt  tip. 

40.  Burning  O  in  H.  To 
show  the  reverse  experiment 
of  burning  O  in  H  or  illu- 
minating gas,  take  a  large 
lamp  chimney,  and  fit  a 
cork  in  each  end.  In  the 
upper  cork,  insert  a  glass  tube  drawn  out  to  a  jet  />. 
In  the  lower  end,  insert  a  bent  glass  tube  J.,  and  a 
metal  tube  C,  made  by  rolling  up  a  strip  of  sheet  iron 
or  brass.  Fit  a  cork  to  the  metal  tube,  and  pass  a  glass 
tube  with  a  Pt  tip  on  it  through  this  cork  {B).  Attach  the  tube  .<4  to  an  H 
generator,  and  when  the  whole  apparatus  is  full  of  11,  ignite  it  at  D  and  C. 
Connect  B  with  a  gasometer  or  bladder  of  O,  then  quickly  insert  the  cork 
into  the  opening  C,  so  as  to  extinguish  the  fl.ame  there.  Let  the  O  pass  in 
sloiHy.  The  O  will  bo  seen  to  burn  in  an  atmosphere  of  H.  Cut  off  the 
supply  of  O,  and  extinguish  all  flames  before  removing  the  supply  of  H, 
to  avoid  an  explosion. 

48. — 41.  Take  some  fresh  crystals  of  sodium  sulphate ;  let  them  lie 
exposed  on  a  piece  of  blotting-paper  for  two  or  three  days.  They  will 
gradually  lose  their  water  and  crumble  down,  or  effinre^e  into  a  white  pow- 
der.    Common  washing  soda  will  do  the  same. 

42.  Take  two  four-ounce  bottles,  and  put  in  each  a  teaspoonful  of  white 
sugar.  Fill  one  bottle  nearly  full  of  piire  rain  or  distilled  water,  the  other 
with  impure  water.  Cork  them,  and  let  them  stand  a  few  days ;  in  one 
bottle  will  be  seen  a  fungoid  growth,  resembling  fuzz  or  lint ;  the  water  in 
the  other  bottle  remains  clear.     (Note,  p.  194.)    The  siwrules  or  germs  that 


DIRECTIONS     FOR     EXPERIMENTS. 


271 


fall  into  the  water  find  suitable  nutriment  for  their  development  in  one 
case,  but  not  in  the  other.  Any  well  or  upring  water  in  which  this  change  takes 
place  is  wiflt  to  drink.     (Page  48,  note.) 

43.  Select  a  thin,  porcelain  dish  which  will  hold  60  or  80  cub.  cm. ; 
place  it  in  one  pan  of  the  balance,  and  trim  a  piece  of  lead  until,  when 
placed  in  the  other  scale-pan,  it  will  counterpoise  the  dish.  Measure  a 
quarter  of  a  liter  of  spring-water,  and  pour  some  of  it  into  the  weighed 
dish  ;  place  it  over  a  very  small  gas-flame,  so  as  to  evaporate  the  H^O  gently, 
without  allowing  it  to  boil ;  add  the  rest  of  the  HoO  from  time  to  time  until 
it  has  completely  evaporated.  Dry  the  salts  thus  obtained,  and  weigh  what 
is  left  as  accurately  as  you  can.  By  multiplying  this  quantity  by  4,  you 
will  obtain  the  amount  of  soluble  solid  substances  per  liter  which  that  par- 
ticular specimen  of  water  contained.  This  is  the  basis  of  the  plan  which, 
with  many  additional  precautions,  is  adopted  for  determining  the  quantity 
of  salts  in  the  process  of  analyzing  waters  to  be  used  for  drinMng  or  manu- 
facturing purposes. 

50. — 44.  The  expansion  of  water  in  freezing  may  be  shown  thus :  Fill 
a  common  round-shouldered  bottle  with  ice-water ;  cork  tightly,  and  place 
in  a  freezing  mixture  (broken  ice  and  salt) ;  or,  if  it  is  a  cold  winter's  day, 
out-of-doors.  The  ice  in  crystallizing  will  either  break  the  bottle,  or  push 
out  the  cork,  which  will  be  found  frozen  on  to  the  end  of  a  stem  of  ice. 
If  the  bottle  be  broken,  it  will  be  seen  that  it  is  completely  filled  with  solid 
ice. 

55.  Carbon.— Small  paste-diamonds  may  be  obtained  of  a  jeweler,  to 
illustrate  the  forms  of  cutting  the  diamond. 

56.-45.  Take  a  glass  cylinder  open  at  both  ends,  and 
suspend  near  the  top  an  inverted  funnel  which  fits  nicely 
into  the  cylinder.  Place  a  bit  of  camphor  burning  on  a 
small  dish  below  it,  so  that  the  smoke  passes  up  into  the 
funnel.  "When  a  considerable  quantity  of  lamp-black  has 
formed  on  the  sides  of  the  cylinder  and  funnel,  extinguish 
the  flame  and  remove  the  lamp.  Then  slowly  lower  the 
funnel,  the  edge  of  which  will  scrape  the  lamp-black  from 
the  sides  of  the  vessel,  in  the  same  manner  that  it  is  done 
by  manufacturers  in  making  lamp-black  for  the  market. 

62.-46.  Place  a  filtering-paper*  in  the  glass  funnel, 
and   in  it  two  ounces  of   bone-black  or  finely  powdered 
charcoal.    Filter  through  it  water  colored  with  ink,  litmus, 
or  any  other  impurities.     In  pouring  the  liquid   into  the  filter,  hold  a  glass 
.rod  against  the  edge  of  the  pouring  vessel,  so  as  to  direct  the  stream  into 
the  funnel.     The  funnel  may  be  placed  in  the  nozzle  of  a  bottle,  but  must 
not  fit  closely.     A  bit  of  wood  or  a  thread  inserted  between  the  stem  of 


*  In  order  to  prepare  this  filter,  fold  a  square  of  filter-paper,  as  shown  in  the  figure 
on  next  page,  first  into  half,  and  then  again  into  a  quarter  of  its  first  size  (6)  ;  cut  off  the 
edges  in  the  direction  of  the  dotted  line  shown  in  the  left-hand  figure  (a),  open  out  the 
folded  paper  (c),  and  drop  it  into  a  funnel  a  little  larger  than  the  paper-cone. 


272 


DIRECTIONS     FOR     EXPERIMENTS. 


the  funnel  and  the  nozzle  will  leave  an  opening  sufficient  for  the  egress 
of  the  air. 

47.  Slip  a  piece  of  freshly-burned  charcoal  under  the  edge  of  a  long  tube 
previously  filled  with  dry  ammonia  gas,*  and  standing  over  Hg.  The  char- 
coal win  quickly  absorb  the  NH3 ;  the  whole  of  the  gas,  if  pure,  will  dis- 
appear, and  the  Hg  will  fill  the  tube. 

48.  Weigh  a  piece  of  freshly-biu-ned  charcoal  as  soon  as  it  is  cold ;  leave 
it  exposed  to  the  air  for  twenty-four  hours,  and  weigh  it  again ;  it  will  bo 
found  to  be  heavier.  Place  the  charcoal  in  a  glass  tube,  and  heat  it  over 
a  lamp ;  moisture  will  be  driven  off,  and  wiU  become  condensed  on  the  cold 
sides  of  the  tube. 

49.  Shake  up  with  a  little  powdered  charcoal  some  stagnant  water  which 
has  been  kept  till  it  smells  offensively.  In  an  hour  it  will  have  lost  all  its 
disagreeable  odor. 

50.  Mix  in  a  mortar  twenty  grams  of  litharge  with  forty  grams  of  NaCl 
and  one  gram  of  powdered  charcoal ;  cover  with  a  little  more  salt,  and  place 
the  mixture  in  a  small  clay  crucible ;  heat  it  to  bright  redness  in  the  fire. 
When  the  mixture  is  melted,  take  the  crucible  out  of  the  fire  and  let  it 
cool.  When  quite  cold,  break  the  crucible,  and  a  bead  of  Pb  will  bo  found 
at  the  bottom,  under  the  melted  salt,  the  C  having  taken  the  O  from  the 
PbO. 

63,-51.  Break  some  marble  into  small  bits  ;  place  them  carefully  in  the 
evolution-flask,  and,  inserting  the  cork  and  tube,  pour  in  HCl  slowly.  The 
gas,  on  account  of  its  weight,  may  bo  pas.sod  directly  into  a  bottle  or  jar, 
and  collected  by  downward  displacement. 

52.  Lower  a  lighted  candle  into  a  jar  of  the  gas,  or,  placing  the  candle 
in  an  empty  jar,  pour  the  gas  into  the  jar,  as  if  it  were  water. 

53.  Test  the  gas  with  moistened  blue  litmus-pajjer. 

64.-54.  In  a  pint  of  water  place  a  piece  of  lime  as  large  as  an  egg ;  let  it 
stand  over  night ;  pour  off  the  clear  liquid  ;  it  is  lime-water.  Place  a  little 
in  a  tumbler  and  pass  a  current  of  COj  from  the  evolution-flask  into  the 
liquid.  It  becomes  milky,  and  then,  after  a  time,  chiar.  If  the  clear  liquid 
bo  boiled,  CO2  is  driven  off,  and  the  lime  is  again  precipitated.     This  is  a 


*  The  gas  may  te  dried  by  passing  it  through  a  tube  filled  with  pieces  of  lime. 


DIRECTIONS     FOR     EXPERIMENTS.  273 

good  illustration  of  the  formation  of  hard  water,  and  of  the  way  in  which 
it  produces  an  incrustation  when  boiled.    (See  p.  49.) 

55.  Repeat  the  experiment  by  breathing  from  the  lungs  through  a  tube 
into  the  lime-water.  The  last  portions  of  air  exhaled  will  be  found  to  be 
most  highly  charged  with  COo. 

Or,  the  formation  of  carbon  dioxide  in  the  lungs  may  be  shown  by  an 
experiment  of  Faraday's.  Fit  an  open-mouthed  receiver  with  a  cork,  through 
which  passes  a  small  bit  of  glass  tubing.  The  receiver  is  then  placed  in  a 
basin  of  water.  Expelling  the  air  from  his  lungs,  the  experimenter  inhales 
the  air  in  the  receiver  through  the  tube.  The  water  in  the  basin  rises  ih. 
the  receiver,  and  shows  how  fast  and  when  the  air  is  exhausted.  Breathing 
back  the  air  from  the  lungs  into  the  receiver  again,  the  water  is  exiieUed, 
ajid  the  lighted  taper  will  test  the  presence  of  the  carbon  dioxide.  Before 
testing,  the  air  may  be  breathed  back  and  forward  two  or  three  times,  until 
it  becomes  unpleasant.  The  rise  and  fall  of  the  water  in  the  jar  is  a  pleasant 
and  instructive  addition  to  the  experiment. 

65. — 56.  Arrange  little  wax-tapers  in  a  wooden  or  pasteboard  trough,  as 
on  page  65.  Light  them,  and  then  pour  in  at  the  top  a  bottle  of  carbon 
dioxide  gas.  If  the  proper  slant  is  given  to  the  trough,  all  the  candles  wiU 
be  extinguished.     (Fig.  26.) 

57.  Balance  a  beaker  on  a  delicate  pair  of  scales,  or  in  any  simple  man- 
ner one's  ingenuity  may  suggest.  Empty  into  it  a  large  jar  of  COj,  and  it 
will  quickly  descend.    (Eig.  27.) 

66.-58.  Twist  a  wire  around  the  neck  of  a  small,  wide-mouthed  vial,  to 
answer  as  a  bucket.  Lower  it  by  the  wire  into  a  jar  of  CO^,  our  ideal  well 
foul  with  the  gas.  Raise  it  again,  and  test  for  the  CO2  by  means  of  a 
lighted  match.     The  bucket  will  be  found  full  of  the  gas. 

70.— 59.  Carefully  heat  in  a  flask  fitted  with  a  cork  and  gas-delivery 
tube  (see  Fig.  8),  5  grams  of  potassium  ferrocyanide  and  50  cc.  of  concen- 
trated HoSOi.  CO  will  come  oflf  freely,  and  will  burn  with  a  blxiish  flame. 
Be  careful  not  to  inhale  the  gas. 

60.  Place  a  few  crystals  of  oxalic  acid  (CoHsOi)  in  a  test-tube,  pour  on 
enough  oil  of  vitriol  to  cover  them,  and  then  heat  gently.  Both  CO  and 
COo  will  be  evolved.  On  applying  a  flame  to  the  open  end  of  the  tube,  the 
CO  will  take  fire  and  burn  with  a  blue  flame.  To  separate  the  two  gases, 
pass  them  through  a  solution  of  KOH,  which  will  remove  the  COo,  and  the 
CO  can  then  be  collected  over  water. 

7  I  .—61.  CH,  may  be  made  by  heating  in  a  test-tube  2  grams  of  sodium 
acetate,  8  grams  of  caustic  soda,  and  2  grams  of  powdered  quicklime. 

72.-62.  Introduce  into  a  retort  which  will  hold  a  lit«r,  10  cc.  of  alco- 
hol and  60  cc.  of  strong  sulphuric  acid.  Heat  the  mixture,  and  collect  the 
gas  over  water ;  continue  the  experinaent  until  the  mass  blackens  and  swells 
up  considerably.  The  product  consists  at  first  chiefly  of  olefiant  gas,  mixed 
with  ether-vapor;  but  toward  the  end  it  becomes  mingled  with  SOo.  Pass 
it  through  a  solution  of  potash,  using  a  wash-bottle  as  shown  in  Fig.  13, 
and  then  collect  in  the  gas-bag.  Fit  a  piece  of  glass  tubing,  drawn  to  a 
fine  point  at  one  end,  to  the  stop-cock  of  the  gas-bag,  by  means  of  a  bit  of 


274  DIRECTIONS     FOR     EXPERIMENTS. 

the  rubber  tubing.     On  turning  the  stoi)-cock  and  forcing  out  the  gas,  it 
may  be  ignited,  ^vhen  it  vnll  bum  with  a  clear  white  light. 

63.  Mis  Cjil,  with  three  times  its  biilk  of  O  and  explode  in  soap-bub- 
bles. Great  care  must  be  taken  not  to  let  the  light  approach  the  gas-bag 
containing  the  mistvire. 

64.  Get  a  bit  of  bituminoiis  coal  about  the  size  of  a  walnut.  Pound  it 
small,  almost  into  dust.  Fill  an  ordinary  tobacco-pipe  (one  with  a  long  stem 
is  preferable)  nearly  full  of  the  pounded  coal,  packing  it  down  closely  with 
your  thumb.  On  the  top  press  a  disk  of  metal  or  a  copper  coin,  and  cover 
with  a  laj'er  of  plaster  of  Paris  or  some  tough  clay,  reduced  to  the  con- 
sistency of  putty  by  being  tempered  with  a  little  water.  Heat  the  bowl  of 
the  pipe  strongly,  and  a  combustible  gas  will  come  out  of  the  stem,  which 
should  now  be  held  in  a  nearly  vertical  jKJsition.  "WTien  no  more  gas  is 
given  off,  and  the  jet  of  flame  goes  out,  remove  the  clay  or  plaster  cover- 
ing.   The  residue  in  the  bowl  is  coke. 

65.  Place  some  bits  of  pine  wood  in  a  glass  i^tort  provided  with  a  per- 
forated cork  and  delivery-tube.  Connect  this  with  an  empty  wash-bottle. 
On  heating  the  retort,  gas  is  given  off,  tar  collects  in  the  wash-bottle  and 
charcoal  remains  in  the  retort.  The  charcoal  used  for  making  gunpowder 
is  prepared  in  this  way  in  large  iron  cylinders. 

74.-66.  Fit  a  cork  to  a  small  test-tube.  Take  out  the  cork,  and  i^ass 
through  it  a  bit  of  glass  tubing  drawn  to  a  fine  point  at  one  end,  so  as  to 
act  as  a  gas-bvu-ner.  Place  in  the  tube  about  two  grains  of  mercury  cyanide ; 
replace  the  cork,  and  heat  over  a  spirit-lamp.  The  test-tube  may  be  suj)- 
ported  by  a  strip  of  thick  paper  twisted  around  it  at  the  top.  Move  the 
tube  to  and  fro  through  the  flame  at  first,  until  it  becomes  fully  heated; 
hold  the  tube  inclined  and  not  perpendicular,  letting  the  flame  strike  the 
side  rather  than  the  bottom.  When  the  gas  begins  to  come  off,  it  may  be 
ignited. 

67.  To  show  the  formation  of  potassium  cyanide  from  a  nitrogenous 
body :  Drop  into  a  i)erfectly  dry  test-tube  a  bit  of  nitrogenous  substance 
and  a  small  piece  of  freshly  cut  K  or  Xa.  Heat  carefully  Tintil  it  melts 
and  a  flash  of  light  is  seen.  When  cold,  break  the  tube,  throw  the  fused 
mass  into  a  clean  test-tube,  and  make  the  test  for  KCy  as  given  below. 

68.  To  test  for  the  presence  of  potassium  cyanide :  Add  to  a  solution  of 
the  suspected  substance  a  few  drops  of  solution  of  sulphate  of  iron  and  a 
slight  excess  of  potash.  Shake  the  precipitate  a  few  moments  with  air  in 
the  tube,  and  add  an  excess  of  hydrochloric  acid,  when  a  blue  precipitate, 
or  a  decided  blue  or  green  color  pervading  the  liquid,  wiU  indicate  the 
presence  of  a  cyanide.    Prussian  blue  is  produced  by  this  process. 

8  I  —69.  The  comiwund  blow-pipe  with  gasometers,  as  shown  in  Fig.  39, 
is  a  serviceable  apparatus.  If  gas-bags  are  used,  the  one  for  H  should  be 
twice  the  size  of  tlie  one  for  O.  A  board  should  be  laid  on  each  bag,  upon 
which  weights  may  be  placet!,  when  rea«ly  for  use,  so  :is  t*)  force  out  the 
gas  steadily.  Alwaj-s  ignite  the  H  first,  and  then  turn  on  the  O  slowly 
until  the  best  effect  is  produced.  All  the  metals  burn  in  the  blow-pipe 
flame  with  their  characteristic  colors.    Narrow  slips  should  be  prepared  for 


DIEECTIONS     FOR     EXPERIMENTS.  275 

this  purpose.  A  cup  for  holding  the  chalk  is  necessary  to  show  the  lime- 
light. A  piece  of  hard  lime,  whittled  to  about  the  size  of  a  pencil,  may  be 
held  in  the  flame  to  illustrate  the  principle. 

89.— 70.  To  a  smaU  gas-jar  fit  a  good  cork,  through  which  pass  a  test- 
tube  as  shown  in  Fig.  43.  Place  the  jar  in  a  large  beaker  glass  or  open- 
mouthed  bottle,  filled  with  spring  water,  which  has  been  mixed  with  a 
fourth  of  its  bulk  of  a  solution  of  carbonic  acid  in  water.  Yill  the  tube 
with  water,  and  place  it  in  the  neck  of  the  jar,  having  introduced  a  few 
sprigs  of  mint  or  the  leafy  branches  of  any  succulent  plant ;  then  expose 
for  an  hour  or  two  in  direct  sunshine.  Bubbles  of  gas  will  be  seen  studding 
the  leaves ;  and  on  shaking  the  jar  they  will  become  detached,  and  will 
rise  into  the  test-tube.  After  a  time  the  cork  and  tube  may  be  withdrawn, 
keeping  the  mouth  of  the  tube  beneath  the  surface  of  the  water;  then 
close  it  with  the  thumb,  turn  the  tube  mouth  upward,  and  test  the  gas 
with  a  glowing  splinter.  The  wood  will  burst  into  a  blaze,  showing  that  the 
gas  consists  mainly  of  O. 

92.  Chlorine.— 71.  Put  in  the  generating  flask  (see  Pig.  44)  a  mixture 
of  equal  parts  of  XaCl  and  MnOa ;  insert  the  cork  with  its  tubes,  and  pour 
in  through  the  funnel  tube  sulphuric  acid  which  has  been  diluted  with  an 
equal  weight  of  water.  On  gently  heating,  the  gas  vn\\  come  off  abun- 
dantly, and  may  be  collected  by  downward  displacement  in  tall  jars  (see  Ex. 
51).  The  gas  may  be  dried  by  passing  it  through  a  wash-bottle  containing 
strong  H0SO4. 

93.-72.  Plunge  a  lighted  candle  into  the  gas:  it  will  burn  feebly,  with 
a  red,  smoky  flame.    (Pig.  45.) 

73.  Place  a  piece  of  dry  phosphorus  in  a  copper  deflagrating  spoon ;  in- 
troduce it  into  a  bottle  of  CI :  the  phosphorus  will  take  fire  and  burn,  while 
suffocating  fumes  of  phosphoric  chloride  (PCls)  are  formed. 

74.  Dip  a  strip  of  blotting-paper  into  oil  of  turpentine ;  plunge  it  into  a 
jar  of  CI :  it  wiU  immediately  burst  into  flame,  while  a  dense  black  smoke 
is  given  off.    (Pig.  46.) 

75.  Powder  some  metallic  Sb  finely  in  a  mortar,  and  sprinkle  into  a  jar 
of  CI :  it  will  take  fire  as  it  falls,  giving  out  fumes  of  antimony  chloride 
(SbCU),  which  are  very  irritating. 

94.-76.  Pill  a  flask  with  water  and  lead  CI  into  it  until  no  more  dis- 
solves. Withdraw  the  tube  through  which  the  CI  has  entered ;  fill  the  flask 
to  its  mouth  with  chlorine  water;  close  it  with  a  cork  in  which  is  a  small, 
short  glass  tube ;  and  support  it  in  an  inverted  position,  so  that  the  end  of 
the  glass  tube  is  below  the  surface  of  water  contained  in  a  beaker.  Place 
in  a  window  where  the  direct  sunlight  will  fall  upon  it.  A  bubble  of  gas 
will  soon  appear  at  the  top  of  the  inverted  flask,  and  will  go  on  increasing 
in  size  from  day  to  day  until  all  the  greenish  color  has  disappeared  from 
the  water.  Then  transfer  the  gas  to  a  test-tube  (see  Pig.  18)  and  test  it 
with  a  spark  on  a  splinter  of  wood.  The  gas  is  thus  proved  to  be  O.  The 
water  in  the  flask  contains  HCl,  as  may  be  shown  by  adding  a  few  drops 
of  silver  nitrate  solution  (see  p.  97). 

77.  Pour  a  little  boiling  water  upon  some   chips  of  logwood,  so  as  to 


276  DIRECTIONS     FOR     EXPERIMENTS. 

obtain  a  deep  red  liquid;  add  some  of  the  solution  of  CI,  and  the  red  color 
will  be  discharged. 

95.-78.  Write  a  few  words  with  ordinary  ink  on  a  printed  card  and 
put  it  in  moist  CI  or  in  chlorine  water.  The  writing  will  be  bleached, 
while  the  printed  words  are  unchanged. 

79.  Print  the  word  Proteus  on  a  large  card,  first  with  the  iodide-of- 
potassium-starch  solution  (note,  p.  101),  and  second  with  a  solution  of 
indigo.  The  former  will  be  white  and  almost  invisible,  the  latter  blue. 
Then  paint  the  words  (using  a  camel's  hair  brush)  with  a  solution  of  chlo- 
rine. The  first  line  will  turn  blue  and  the  second  white,  thus  just  reversing 
their  color. 

80.  Bleach  some  colored  cahco  by  putting  it  into  water  with  which  a 
little  bleaching  powder  has  been  mixed.  The  action  is  hastened  by  adding 
a  little  vinegar  or  a  few  drops  of  any  dilute  acid. 

96.— 81.  Burn  H  in  CI,  as  shown  in  experiment  of  burning  H  in  O.  (Ex.  40.) 

82.  "Wrap  a  soda-water  bottle  in  a  towel;  fill  it  with  water,  and  invert 
it  in  the  pneumatic  tub.  Introduce  a  glass  funnel  into  the  neck,  and 
having  filled  a  jar  of  100  cc.  capacity  with  CI,  pass  the  gas  into  the  bottle. 
Fill  the  same  jar  with  H,  and  empty  into  the  same  bottle ;  withdraw  the 
funnel,  close  the  neck  with  the  palm  of  the  hand,  lift  the  bottle  out  of  the 
water-bath,  give  it  a  shake  to  mix  the  gases,  and  apply  a  light.  A  sharp 
explosion  will  immediately  follow,  and  gaseous  HCl  be  formed.  Equal 
measures  of  H  and  CI  unite  in  this  way,  and  the  gas  produced  occupies  the 
same  bulk  that  its  components  did  when  separate.  Sunlight  will  also  cause 
the  explosion  of  a  mixture  of  CI  and  H. 

83.  To  prepare  HCl  put  some  common  salt  in  the  generating  flask 
(Fig.  47),  and  pour  through  the  funnel  tube  about  twice  its  weight  of 
strong  HoSO,.  A  solution  of  the  gas  —  ordinary  hydrochloric  acid  — is 
obtained  by  leading  it  through  water,  as  sho'mi  in  the  cut.  The  gas  itself 
may  be  collected  for  experiment  by  downward  displacement,  as  in  the  case 
of  CI. 

The  gas  may  also  be  obtained  by  gently  heating  concentrated  hydro- 
chloric acid.  In  this  case  it  should  be  dried  by  leading  it  through  strong 
HoSO.  in  a  wash-bottle,  before  collecting  it  for  experiment. 

84.  A  candle  lowered  into  a  jar  of  HCl  gas  is  extinguished. 

85.  Fill  two  jars  of  the  same  size,  the  one  with  HCl  gas,  the  other  with 
NHj.  Bring  them  mouth  to  mouth  and  remove  the  glass  plates  by  which 
they  were  closed.  The  two  gases  immediately  combine,  forming  a  white 
cloud  of  ammonium  chloride. 

86.  Dilute  a  little  HCl  with  six  or  eight  times  its  bulk  of  water,  and 
add  caustic  soda  cautiously,  until  the  liquid  is  neutral,  and  neither  reddens 
blue  litmus  nor  restores  the  blue  to  red  litmus-paper.  Poiir  the  liquid  into 
a  basin,  and  evaporate  it  slowly ;  crystals  of  NaCl  will  be  deposited  in 
cubes. 

87.  Boil  HCl  in  a  test-tube  with  fragments  of  gold-leaf,  or  a  bit  of 
platinum  wire ;  they  will  not  be  dissolved.  Now  add  a  drop  or  two  of 
HNO3 ;  a  yeUow  solution  will  be  formed. 


DIRECTIONS     FOR     EXPERIMENTS.  277 

88.  Fill  a  test-tube  nearly  full  of  pure  rain  or  snow  water,  and  add  a 
drop  or  two  of  the  nitrate  of  silver  solution.  A  drop  of  HCl  will  cause  a 
cloudy,  white  precipitate.* 

I  00.  Jironiine  and  Iodine.— 89.  Pour  a  little  strong  HjSOt  onto  a  few 
crystals  of  potassium  bromide  in  a  test-tube.  Heavy  red  vapor  of  Br  will 
fill  the  tube. 

90.  Dissolve  in  a  little  water  in  a  test-tube  a  crystal  of  potassium  bro- 
mide; add  a  little  chlorine  water.  Br  is  set  free,  and  the  solution  becomes 
brownish  in  color;  now  add  a  few  drops  of  chloroform,  and  shake 
thoroughly.  When  the  chloroform  settles  to  the  bottom,  it  is  colored 
yellow  by  the  Br  it  has  dissolved.  If  dilute  starch  paste  is  added  instead 
of  the  chloroform,  it  also  becomes  yellow. 

91.  Repeat  experiments  89  and  90  with  potassium  iodide  instead  of 
potassium  bromide.  Violet  vapor  of  iodine  will  be  given  off  in  the  first; 
the  chloroform  will  acquire  a  beautiful  violet  color,  and  the  starch  paste 
will  become  dark  blue. 

I  03.  Snfj^Jttir.— 92.  Melt  a  quantity  of  S,  either  the  flowers  or  brim- 
stone, in  a  test-tube.  If  heated  carefully  and  uniformly,  the  liquid  S  is  at 
first  thin  and  amber-colored ;  then  becomes  dark,  and  so  thick  that  at  a 
certain  point  it  will  not  run  from  the  inverted  test-tube ;  and  finally,  at  a 
higher  temperature,  regains  its  fluidity  and  boils,  giving  off  a  deep  red 
vapor,  which  readily  burns.  Pour  the  liquid  S  into  water.  It  forms  an 
elastic  gum,  which  slowly  hardens  and  becomes  brittle. 

93.  Fill  a  clay  crucible  or  a  cup  with  brimstone,  and  melt  it  with  a 
gentle  heat.  Set  it  aside  to  cool.  When  a  crust  has  formed  on  top,  break 
it,  and  pour  out  the  liquid  contents.  If  the  cup  be  broken  when  cold,  the 
interior  will  be  found  filled  with  long  amber-colored  transparent  crystals 
of  S,  which  after  a  time  become  opaque  and  yellow. 

94.  Pulverize  some  brimstone,  and  put  in  a  test-tube  and  cover  with 
CSj.  Put  the  tube  in  warm  water  until  the  S  dissolves,  then  cork  it  tightly, 
or,  better,  pour  the  solution  onto  a  watch-glass  under  a  bell-jar,  and  let  it 
stand  until  crystals  separate.  They  have  a  different  form  from  those 
obtained  from  fusion.  The  more  slowly  they  separate,  the  larger  they 
will  be. 

95.  Put  a  piece  of  S  in  a  test-tube,  and  above  it  some  copper  turnings 
or  scraps.  Heat  the  sulphur  until  it  boils.  The  Cu  burns  brightly  in  the 
vapor  of  S.    Fe  and  Pb  will  also  burn  in  S  vapor. 

I  04. — 96.  Dissolve  in  a  little  water  a  crystal  of  potassium  perman- 
ganate. On  leading  SO2  into  the  solution,  or  adding  a  little  sulphurous 
acid,  the  solution  becomes  colorless. 

I  05. — 97.  Mix  a  little  sulphurous  acid  and  chlorine  water.  The  presence 
of  HCl  and  HoSOi  can  be  shown  by  the  silver  nitrate  and  barium  chloride 
tests  (pages  97  and  109). 

I  08.— 98.  The  method  of  making  HjSO.  may  be  finely  illustrated  by 

*  Well  water,  which  gives  a  considerable  precipitate  with  AgNO^,  is  usually  unfit  to 
drink,  owing  to  sewage  contamination. 


278  DIRECTIONS     FOR     EXPERIMENTS. 

means  of  the  apparatus  shown  in  Fig.  51.  The  large  glass  globe  takes  the 
place  of  the  leaden  chambers.  Of  the  two  flasks  at  the  left,  one  contains 
strips  of  Cu  and  strong  HaSO,,  for  the  production  of  SOj  (see  p.  104) ;  the 
other  contains  water,  to  furnish  a  supply  of  steam ;  NO  is  supplied  from 
the  generator  at  the  right  (see  p.  33) ;  air  is  introduced  from  a  small 
bellows,  or  the  mouth,  through  the  long  rubber  tube,  while  the  straight, 
upright  glass  tube  acts  as  a  chimney  for  the  escape  of  waste  gases.  If  the 
supplies  of  NO  and  air  are  cut  off  after  the  globe  is  filled  with  ruddy 
fumes,  the  gases  filling  the  globe  will  soon  become  nearly  or  quite  colorless, 
from  the  reduction  of  NO2  to  NO ;  on  introducing  a  little  air,  the  red  color 
reappears. 

99.  Pour  a  little  strong  sulphuric  acid  into  a  test-tube.  Place  a  splinter 
of  wood  in  it ;  the  wood  will  be  blackened  in  a  few  minutes.  Poiir  1  cc.  of 
strong  H2SO4  into  a  tube  containing  3  or  4  cc.  of  water;  considerable  heat 
will  be  felt  to  attend  the  mixture.*  Take  a  little  of  this  diluted  acid,  and, 
with  a  feather  dipped  into  it,  trace  a  few  letters  ujwn  writing-paper.  Hold 
the  paper  near  the  fire  :  the  water  will  evaporate,  leaving  the  acid  behind ; 
this  will  soon  blacken  the  paper. 

100.  Mix  4  oz.  HoSO,  and  1  oz.  pounded  ice  or  snow.  Stir  it  with  a 
test-tube  containing  a  little  ether ;  the  ether  soon  boils. 

101.  Mix  1  t;z.  H2SO4  with  4  oz.  snow  or  pounded  ice,  and  stir  it  with 
a  test-tube  containing  cold  water;  the  water  soon  freezes.  The  vessel  in 
which  the  experiment  is  performed  usually  freezes  fast  to  the  table,  so  that 
it  is  well  to  set  in  on  a  plate  or  small  board. 

102.  Dissolve  some  sugar  in  a  very  little  water,  so  as  to  form  a  thick 
syrup.  Put  it  in  a  tall  beaker,  and  pour  on  strong  H2.SO4  until  it  begins  to 
swell  up  and  blacken.  The  HoSO.  removes  the  HoO  from  the  sugar,  leaving 
only  C  behind. 

I  09.— 103.  Place  in  an  evolution  flask  {A,  Fig.  52)  a  few  lumps  of  fer- 
rous sulphide,  and  add  some  dilute  HjSO..  Dead  the  HjS  gas  through  a 
solution  of  copper  sulphate  in  B,  one  of  tartar  emetic  in  C,  one  of  arsenic  in 
D,  one  of  zinc  sulphate  in  E,  and  finally  into  water  in  the  beaker.  Pre- 
cipitates—sulphides of  the  metals— will  be  produced,  brownish -black  in  B, 
orange  in  C\  yellow  in  2),  and  white  in  E.  (See  chapter  on  "Qualitative 
Analysis.") 

I  I  O. — 104.  Place  a  few  drops  of  the  disulphide  in  each  of  four  test- 
tubes.  To  one  add  a  little  powdered  sulphur,  to  a  second  a  few  minute 
scales  of  iodine,  to  a  third  a  fragment  of  phosphorus,  and  to  a  fourth  a  few 
drops  of  M^ater.  Notice  the  beautiful  color  produced  })y  the  iodine;  the 
solution  of  the  sulphur  and  the  phosphorus ;  the  insolubility  of  the  liquid 
in  water ;  and  also  its  refractive  power. 

105.  The  experiment  of  burning  P  under  water  may  be  easily  shown  by 
throwing  a  piece  of  P  into  a  glass  of  hot  water.  It  melts,  and  looks  like  a 
thick  oil  under  the  water.  A  fine  stream  of  O  gas  may  then  be  passed 
through  a  glass  tube  down  to  the  P,  which  burns  brightly  under  water. 

*  In  mixing  HjSO,  and  HjO,  always  pour  the  acid  hi/o  the  water. 


DIRECTIONS     FOR     EXPERIMENTS.  279 

I  I  4.  PJiosphorus.—lOG.  Dissolve  1  or  2  decigrams  of  phosphorus  in 
2  cc.  of  carbon  disulphide  in  a  test-tube ;  pour  a  little  of  the  solution 
upon  a  piece  of  filtering-paper,  and  allow  it  to  dry.  The  phosphorus 
will  be  left  in  a  finely-divided  form,  and  will  set  fire  to  the  paper  in  a  few 
minutes. 

107.  Place  a  bit  of  phosphorus  in  a  solution  of  silver  nitrate.  In  the 
course  of  a  day  or  two,  it  will  be  covered  with  brilliant  crystals  of  reduced 
silver.    Repeat  with  CuSO,  solution. 

I  I  6. — 108.  To  prepare  hydrogen  phosphide,  place  in  the  flask  (a,  Pig.  54) 
a  strong  solution  of  caustic  potash  and  a  few  small  pieces  of  phosphorus. 
The  addition  of  a  little  ether  will  serve  to  expel  the  air,  and  prevent  the 
danger  of  an  explosion.  Regular  smoke-rings  will  be  formed  onlj'  in  per- 
fectly still  air. 

I  19.  --irsenic.— 109.  Compoiinds  of  As,  when  heated  on  charcoal,  give 
off  a  garlic  odor. 

110.  Add  a  few  drops  of  a  solution  of  arsenic  trioxide  to  200  or  300  cc. 
of  water,  and  then  3  or  4  cc.  of  HCl ;  place  in  the  liquid  two  or  three 
slips  of  bright  copper  foil,  and  boil  the  whole  for  a  few  minutes :  the  cop- 
per foil  will  become  coated  with  a  steel-gray  film.  Part  of  the  Cu  becomes 
dissolved  and  displaces  the  arsenic,  which  is  thrown  down  on  the  undis- 
solved portion.  Pour  off  the  water,  dry  the  Cu  on  blotting-paper,  and  heat 
the  foil  in  a  tube,  sealed  at  one  end.  The  arsenic  will  sublime,  condensing 
in  minute  octahedra  on  the  cold  sides  of  the  tube.  This  is  Eeituch''s  test  for 
arsenic. 

1  22.  Jioron. — 111.  Make  a  small  round  loop  at  the  end  of  a  thin 
platinum  wire.  Dip  the  hot  loop  into  powdered  borax,  and  heat  the  ad- 
hering salt  until  it  melts  to  a  clear,  transparent  bead.  Moistened  with  a 
solution  of  cobalt  nitrate  and  heated,  the  bead  becomes  blue ;  with  man- 
ganese dioxide,  or  any  manganese  salt,  the  clear  bead  changes  on  heating 
to  an  amethyst  color. 

112.  Add  to  a  solution  of  boric  acid  (or  borax  and  HoSO.),  in  a  small 
dish,  a  little  alcohol.  Set  fire  to  the  alcohol,  and,  as  it  burns,  stir  the  solu- 
tion with  a  glass  rod.     The  flame  is  tinged  green. 

113.  A  similar  green  coloration  is  obtained  by  bringing  a  little  boric 
acid  (or  borax  moistened  with  HsSO.)  into  the  Bunsen  flame  on  a  platinum 
wire,  which  has  first  been  dipped  in  glycerin. 

Silicon.— 114:.  Grind  in  the  mortar  3  or  4  grams  of  fluor  spar,  and  mix 
with  an  equal  weight  of  powdered  glass  or  sand.  Introduce  it  into  a  flask 
pre-\aously  fltted  with  a  sound  cork  and  a  tube,  as  in  the  figure.  Pour  upon 
the  mixture  30  grams  of  strong  HoSO,,  insert  the  cork  and  tube,  and  apply 
a  gentle  heat :  a  densely  fuming  gas  is  disengaged,  consisting  of  silicic 
fluoride  (SiP.).  This  gas  must  not  be  inhaled,  as  it  is  very  irritating.  Pass 
it  into  a  glass  of  11,0,  having  suflBcient  Hg  at  the  bottom  to  cover  the 
mouth  of  the  delivery-tube.  Each  bubble  of  gas,  as  it  rises,  is  coated  with 
a  white  film  of  hydrated  silica,  while  a  solution  of  hydrofluosilicic  acid 
(2HP,Sir.)  is  formed.  The  deposit  of  silica  would  clog  the  tube  if  it  were 
not  for  the  Hg ;  hence  the  tube  must  be  kept  dry,  which  is  best  accom- 


280 


DIRECTIONS     FOR     EXPERIMENTS. 


plished  by  placing  it  in  position  in  the  Hg,  then  pouring  water  carefully 

into  the  glass  on  the  Hg. 
Filter  the  solution,  and  pre- 
serve it  as  a  test  for  Ba  and 
K. 

115.  Grind  a  little  glass 
to  a  fine  powder  in  a  mortar ; 
place  it  on  a  piece  of  moist- 
ened red  litmus-paper ;  suffi- 
cient alkali  will  be  dissolved 
by  the  water  to  tinge  the 
paper  blue. 

116.  Mix  a  little  fine  sand 
with  KNO3  and  Na^COa,  and 
heat  strongly  on  a  strip  of 
Pt  foil  for  five  minutes. 
When  cold,  it  will  dissolve 
in  H„0. 

117.  Take    some    of    the 
silica  obtained  in  the  experi- 
ment  of    making    2H:F,SiT'., 
and   put   it   in   a  strong  so- 
lution of  KOH,  and  boil.      It  "will  dissolve.* 

118.  Take  four  glass  cylinders,  five  inches  high,  and  pour  into  each  about 
1  oz.  of  ordinary  water-glass  and  4  oz.  of  water.  Drop  into  one  a  few 
crystals  of  iron  sulphate,  into  another  some  crystals  of  blue  vitriol,  into  the 
third  white  vitriol,  into  the  fourth  a  crystal  of  each.  Let  them  stand 
quietly  for  twenty-four  hours.  In  the  first  green  fibers  will  be  seen,  re- 
sembling very  closely  a  growing  plant ;  blue  and  white  ones  will  appear  in 
the  others.    If  closely  corked,  they  can  bo  kept  for  weeks. 

119.  Pour  1  oz.  of  water-glass  into  a  capsule,  and  pour  on  it  half  as  much 
H2SO,,  taking  care  that  the  two  do  not  mix.  Pour  immediately,  but 
slowly,  into  a  second  capsule ;  the  silica  separates  in  long  tubes  resembling 
stalactites. 

I  28.  I'ota.s.siinn.—X^O.  Place  30  granus  of  pearlash  in  a  half -liter  bottle, 
and  dissolve  it  in  350  cc.  of  water.  Shake  20  grams  of  quicklime  with  five 
or  six  times  its  bulk  of  water,  and  add  the  pasty  mixture  (aboxit  120  cc. 
in  bulk)  to  the  boiling  solution  of  pearlash.  Agitate  the  mixture,  and  let 
it  stand  till  it  is  clear.  Pour  off  a  portion  of  the  liquid :  it  is  a  solution  of 
caustic  potash.  Add  to  it  some  HCl :  no  effervescence  will  occur.  Agitate 
a  tablespoonful  of  olive-oil  in  a  small  vial  with  3  or  4  cc.  of  the  caustic 
solution  diluted  with  ton  times  its  bulk  of  water :  a  milky-looking  liquid 
will  be  formed,  which  is  the  first  stage  in  the  making  of  soap. 


♦  The  infusorial  silica,  sold  under  the  name  of  electro-silicon,  will  dissolve  in  KOH 
in  the  same  manner.  A  basic  silicate,  known  as  "water-glass,"  or  "soluble  glaes,"  is 
prepared  in  this  way. 


DIRECTIONS     FOR     EXPERIMENTS.  281 

121  Biirn  some  dry  brushwood ;  collect  the  ash,  wash  it  with  five  or  six 
times  its  bulk  of  water,  and  filter.  Test  the  solution  with  a  piece  of  red- 
dened litmus-paper,  which  will  become  blue.  Evaporate  the  solution  to 
dryness  in  a  small  porcelain  dish.  If  the  dry  mass  be  left  exposed  to  the 
air  for  a  few  hours,  it  will  become  moist.  The  potassium  carbonate,  of 
which  it  chiefly  consists,  atti-acts  moistiire  rapidly,  and  deliquesces.  To  a 
portion  of  the  salt,  add  a  few  drops  of  HCl :   brisk  eflfervescence  occurs. 

I  29. — 122.  Pulverize  finely  nitrate  of  potash  and  chloride  of  ammonium, 
five  parts  of  each,  and  mix  with  sixteen  parts  of  water.  The  temperature 
of  the  mixture  will  be  reduced  so  low  that,  if  a  test-tube  with  a  Uttle 
water  in  it  be  used  to  stir  it,  the  water  in  the  tube  will  be  converted 
into  ice. 

I  3  I  .—123.  Into  a  dilute  solution  of  KOH,  lead  CI  gas  until  no  more  is 
absorbed.  Evaporate  the  solution  until  crystals  are  formed.  These  consist 
of  potassium  chlorate,  KCIO3.  Separate  them  from  the  liquid,  and  dry  by 
pressing  between  folds  of  filter  paper. 

124.  To  demonstrate  the  oxidizing  power  of  KCIO3 :  Put  into  the  mortar 
as  much  potassium  chlorate  as  will  lie  upon  the  point  of  a  knife-blade,  and 
half  as  much  sulphur.  Cover  the  mortar  with  a  sheet  of  writing-paper, 
having  a  hole  cut  in  it  just  large  enough  for  the  handle  of  the  pestle  to 
pass  through.  "Wlien  the  two  substances  have  become  thoroughly  mixed, 
grind  heavily  with  the  pestle,  when  rapid  detonations  wdll  ensue.  The 
paper  will  prevent  loose  particles  from  fljang  into  the  eyes.  The  same  pre- 
caution should  always  be  observed  when  pulverizing  potassium  chlorate.  A 
better  way  is  to  purchase  that  salt  in  powder,  or  to  make  a  hot  saturated 
solution,  and  pour  it  out  in  thin  films  on  panes  of  glass  or  old  plates.  It 
then  forms  very  small  crystals,  which  can  be  scraped  off  and  dried  for  use. 
After  using,  clean  out  the  mortar  carefully  for  other  experiments.  The 
powder  can  be  wrapped  with  paper  into  a  hard  pellet,  and  exploded  on  an 
anvil  by  a  sharp  blow  from  a  hammer.  Sometimes  small  bits  of  phosphomas 
are  used  instead  of  sulphur.  Great  care  is  then  necessary,  as  the  particles 
of  burning  phosphorus  are  apt  to  fly  to  some  distance. 

125.  If  four  measures  of  a  cold  saturated  solution  of  potassium  bichro- 
mate be  mixed  with  six  of  concentrated  HaSd,  and  the  liquid  be  allowed 
to  cool,  cfiromic  anhydride  crystallizes  in  crimson  needles,  which  may  be 
drained  and  dried  ujwn  a  brick. 

The  chromic  anhydride  is  a  pow^erful  oxidizing  agent,  as  may  be  shown 
by  dropping  onto  some  of  the  dry  crystals  a  little  strong  alcohol.  The 
alcohol  will  inflame,  while  the  chromic  anhydride  turns  green. 

J  32.  Sodium.— 12G.  Take  a  small  saucepan,  and,  having  made  a  little 
pool  of  water  upon  a  wooden  stool,  set  the  saucepan  upon  it ;  then  throw  in 
a  handful  of  snow  or  powdered  ice,  and  a  handful  of  common  salt ;  now 
stir  with  a  stick,  and  the  cold  will  freeze  the  saucepan  to  the  stool,  even 
before  a  large  fire. 

127.  Pill  a  tall  cylinder  with  a  clear  saturated  solution  of  NaCI,  and  pass 
into  it  at  the  same  time  strong  currents  of  ISTHa  and  COo  gases.  A  pre- 
cipitate of  NaHCGj  falls.     This  is  known   as   the   Solvay  Ammonia  soda 


282  DIRECTIONS     FOR     EXPERIMENTS. 

process.     The  solution  contains  NH,C1,  from  which  NH3  may  be  recovered 
by  treating  it  wath  OaO. 

128.  Dissolve  150  parts,  by  weight,  of  hypostdphite  of  soda  in  15  i)arts 
boiling  water,  and  gently  pour  it  into  a  tall  test-glass  so  as  to  half  fill  it, 
keeping  the  solution  warm  by  placing  the  glass  in  hot  water.  Dissolve  100 
parts,  by  weight,  of  sodium  acetate  in  15  parts  hot  water,  and  carefully 
pour  it  in  the  same  glass  ;  the  latter  will  form  an  overlying  layer  on  the 
surface  of  the  former,  and  will  not  mix  with  it.  "V\Tien  cool,  there  will  be 
two  supersaturated  solutions.  If  a  crystal  of  sodium  hyposulphite  be  at- 
tached to  a  thread,  and  carefully  passed  into  the  glass,  it  will  traverse  the 
acetate  solution  without  disturbing  it,  but,  on  reaching  the  hjTJOsulphite 
solution,  will  cause  the  latter  to  crystallize  instantaneously  in  large  prisms. 
(Compare  note,  p.  134.) 

129.  Dissolve  40  grs.  of  common  soda  in  one  wine-glass  of  water,  and 
35  grs.  of  tartaric  acid  in  another.  On  being  jioured  together  in  a  goblet, 
they  will  violently  effervesce.  X^se  a  glass  which  is  large  enough  to  prevent 
any  of  the  liquid  from  running  over.  Neatness  in  experiments  is  essential 
to  perfection,  and  often  to  success.  At  the  close  of  this  illustration,  evap- 
orate the  solution,*  and  a  neutral  salt  will  result.    (Compare  p.  98). 

I  38.  Cnlciutn. — 130.  Place  a  few  lumps  of  marble  in  the  open  fire,  or  in 
an  open  crucible  with  a  hole  at  the  bottom,  and  heat  it  strongly  for  an 
hour  or  two.  It  is  converted  into  quicklime.  Place  the  lumps  in  an  open 
dish,  and  cover  them  with  water— about  one  third  the  weight  of  the  lime. 
The  water  will  be  aU  absorbed  by  the  lime,  and  slaked  lime  Ca(0H)2  pro- 
duced. 

I  39.— 131.  Put  some  of  the  Ca(OH)2  in  a  bottle  of  water,  and  cork.  The 
water  dissolves  a  very  little  of  the  Ca(OII)j,  and  the  clear  solution  forms 
"lime-water."  (Compare  Ex.  54.)  It  may  be  decanted  or  siphoned  off,  and 
a  fresh  supply  made  by  simply  filling  up  the  bottle  again.  This  may  be  re- 
peated as  long  as  solid  Ca(OII),  remains  in  the  bottle. 

132.  Pour  some  of  the  lime-water  into  a  saucer,  and  let  it  stand.  It 
becomes  covered  with  a  film  which  may  be  shown  to  be  a  carbonate  by 
removing  it,  placing  it  in  a  test-tube,  and  adding  a  drop  of  HCl.  Efferves- 
cence will  occur,  and  the  gas  which  comes  off  will  render  turbid  a  drop  of 
clear  lime-water  introduced  into  the  mouth  of  the  test-tube  on  th'e  end  of  a 
glass  rod. 

I  4  I  .—133.  Select  a  medal  suital)le  for  the  purpose  ;  paste  a  shallow  rim 
of  paper  round  it,  so  as  to  make  it  like  the  lid  of  a  piU-box,  and  anoint  the 
surface  of  the  medal  very  lightly  with  oil.    Mix  a  little  dry  plaster  of  Paris 

*  Pour  a  part  of  the  liquid  into  an  evaporating  dieh,  and  place  this  on  the  tripod 
over  the  flame  of  the  spirit-lamp,  or  ujjon  a  hot  stove.  Heat  until  a  drop  of  the  liquid, 
taken  out  on  the  end  of  a  glass-rod  and  put  on  a  bit  of  glass,  will  crystallize  as  soon  as  it 
cools.  Then  set  the  dish  aside  to  cool,  when  crystals  will  soon  begin  to  form. — In  tliis 
connection,  it  is  well  to  remark  that  a  cook  xtore  u'ill  be  fofund  of  great  nse  in  chemical 
experiments,  and  indeed  may,  in  the  laboratory,  take  the  place  of  the  furnace.  The  oven 
will  dry  apparatus  and  chemicals;  the  heat  is  suftlcicnt  for  evaporating  solutions,  distill- 
ing water,  etc.,  while  an  excellent  sand  or  water-bath  may  be  readily  contrived. 


DIRECTIONS     FOR     EXPERIMEZSTTS.  283 

"With  water  till  it  becomes  of  the  consistence  of  thin  cream;  .apply  it 
carefvilly  with  a  hair-pencil  to  every  part  of  the  surface,  so  as  to  exclude 
air-bubbles;  then  poiir  a  thicker  mixture  into  the  mold.  Allow  it  to 
remain  for  an  hour.  The  cast  may  then  be  removed :  it  will  be  a  reversed 
copy  of  the  medal. 

I  43.  See  Experiment  80. 

134.  Dissolve  a  little  piece  of  marble  in  HCl  (see  Ex.  51).  Clean  one  end 
of  a  thin  platinum  wire  by  dipping  it  in  HCl,  and  then  holding  it  in  the 
flame  of  a  Bunsen  burner  repeatedly  until  it  imparts  no  color  to  the  flame 
when  first  introduced.  Then  dip  the  wire  into  the  CaCU  solution,  and  hold 
it  in  the  flame.  An  orange-red  flame  coloration  will  be  obtained,  which  is 
characteristic  of  calcium. 

135.  Repeat  the  last  experiment  with  SrCla  and  with  BaClj. 

1 44.  Maf/nesiiim.— 136.  Burn  a  piece  of  magnesium  ribbon.  It  is 
readily  kindled  by  a  candle  or  match. 

I  48.— 137.  Repeat  Ex.  134  with  solutions  of  K,  Na,  Li,  Cs,  Cu.  The 
wire  must  be  carefully  cleaned  before  making  the  experiment  with  each. 

151.  Iron.— 138.  Pulverize  a  salt  of  iron,  and  heat  it  with  NajCOa  on 
charcoal  before  the  blow-pipe.  A  black  powder  is  obtained,  which  is  at- 
tracted by  the  magnet. 

139.  Mix  some  iron  filings  with  twice  the  bulk  of  flowers  of  sulphur. 
Heat  the  mixture  in  a  hard  glass  tube.  The  two  will  unite  and  form 
ferrous  sulphide  PeS,  which  yields  H^S,  when  treated  with  dilute  H^SO, 
(see  p.  109). 

I  57.— 140.  Make  a  strong  solution  of  potassium  permanganate,  and 
heat  to  boiling  in  a  test-tube.  Pour  in  a  few  drops  of  glycerin ;  the 
latter  is  oxidized  so  violently  that  a  flash  may  be  seen,  and  part  of  the 
liqtiid  is  ejected  from  the  test-tube. 

161.  Co j)per.— 14:1.  Fill  a  test-tube  nearly  full  of  H2O.  Pour  in  it  a  few 
drops  of  the  solution  of  copper  sulphate.  Add  NH4OH,  and  a  greenish-blue 
precipitate  will  be  formed,  which  dissolves  when  more  NH.OH  is  added, 
yielding  a  dark-blue  solution.  The  copper  sulphate  may  be  readily  pre- 
pared for  this  experiment  by  heating  a  copper  cent  with  strong  sulphuric 
acid.  This  experiment  may  be  made  to  show  the  divisibility  of  matter  by 
weighing  the  cent,  finding  what  proportion  of  the  whole  solution  you  use, 
and  then  experiment  to  see  what  quantity  of  water  can  be  taken,  and  yet 
have  the  blue  color  perceptible  in  the  ammonia  test. 

142.  Besides  the  ammonia  test  for  copper,  the  metal  may  be  detected  by 
the  red  metallic  deposit  formed  on  an  iron  nail,  dipped  into  a  solution  of 
the  salt. 

143.  Dissolve  a  piece  of  Cu  in  HNO3  (see  p.  33).  Evaporate  to  a  small 
quantity  the  solution  which  is  obtained,  and  allow  it  to  cool.  If  sufficiently 
concentrated,  crystals  of  Cu2]sr03  will  be  formed. 

144.  Repeat  Ex.  143  with  Cu  and  strong  H^SO,  (see  p.  104).  The  blue 
crystals  are  CuSO,. 

I  63.  Tjend. — 145.  If  a  water  contain  lead,  even  in  minute  quantity,  its 
presence  is  easily  ascertained  by  taking  two  similar  Jars  of  25  cm.  high 


284  DIRECTIONS     FOR     EXPERIMENTS. 

of  colorless  glass,  filling  both  of  them  with  the  water,  and  adding  to  one  of 
the  jars  3  or  4  cc.  of  a  solution  of  sulphuretted  hydrogen.  A  quantity  of 
lead  less  than  one  part  in  two  millions  is  easily  perceived  by  the  brown 
tinge  occasioned,  on  looking  down  upon  a  sheet  of  white  paper ;  the  jar  to 
which  the  test  has  not  been  added  serv-ing  as  a  standard  of  comjiarison. 

I  65 .  frold.— 14:6.  Place  a  little  gold-leaf  in  two  test-tubes ;  to  one  add 
IINO3,  to  the  other  HCl.  Even  when  heated,  the  gold-leaf  wiU  remain  un- 
affected in  each.  Pour  the  contents  of  one  tube  into  the  other :  the  Au 
will  disappear  with  effervescence.  Evaporate  this  solution  in  a  small 
porcelain  dish  tUl  the  acid  is  nearly  all  driven  off:  gold  chloride  wiU 
be  left. 

147.  Dilute  the  solution  with  3  or  4  cc.  of  H.O.  To  a  jxDrtion  of  this 
liquid  add  a  solution  of  ferrous  sulphate :  a  brown  precipitate  of  finely- 
di^^ded  redxiced  Au  is  obtained,  and  iron  chloride  is  formed. 

167.  Silver.— 14S.  Dissolve  a  ten-cent  piece  in  HNO3.  The  solution  has 
a  bluish  color,  owing  to  the  presence  of  the  Cu.  Dilute  with  200  cc.  of 
water ;  then  add  a  solution  of  XaCl  so  long  as  it  forms  a  precipitate ;  white 
flakes  of  silver  chloride  are  formed.  Stir  the  mixture  briskly  with  a  glass 
rod  ;  the  precipitate  of  AgCl  will  collect  into  clots.  Filter  the  solution.  The 
presence  of  Cu  in  the  clear  liquor  may  be  proved  by  adding  to  a  portion  of 
the  liquid  NHtOH  in  excess :  a  blue  solution  is  formed.  Place  the  blade 
of  a  knife  in  another  portion  of  the  filtrate  :  it  will  become  coated  with 
metallic  Cu. 

149.  Take  the  precipitated  silver  chloride,  and,  after  ha^nng  washed  it 
well  on  a  filter,  place  it  in  a  wine-glass  with  a  little  water;  add  two  or 
three  droiis  of  II^SO.,  and  then  place  a  slip  of  Zn  in  contact  with  the 
chloride,  and  leave  it  for  twenty-four  hours.  The  chloride  will  be  reduced 
to  metallic  Ag,  which  will  have  a  gray  porous  aspect,  while  zinc  chloiide 
will  be  found  in  solution.  Lift  out  the  piece  of  Zn  carefully ;  wash  the  Ag 
first  with  water  containing  a  little  H,SO,,  then  with  pure  HjO.  Drj'  the 
residue.  Place  a  small  quantity  of  it  upon  an  anvil,  and  strike  it  a  blow 
with  a  hammer;  a  bright  metallic  surface  will  be  produced.  Place  a  little 
of  the  gray  jxjwder  upon  charcoal,  and  heat  in  the  flame  of  a  blow-pipe : 
it  will  melt  into  a  brilliant  malleable  bead.  Dissolve  another  portion  in 
IINO3 ;  red  fumes  will  escape,  and  silver  nitrate  be  obtained  in  solution. 

150.  Fill  a  vial  half  full  of  a  solution  of  silver  nitrate,  and  add  a  few 
globules  of  Hg.  The  Ag  will  be  precipitated  in  a  few  days,  forming  the 
"  silver  tree." 

151.  Place  a  crystal  of  AgNO^  on  a  piece  of  charcoal,  and  heat  in  the 
reducing  blow-pipe  flame.  A  globule  of  metallic  Ag  is  produced,  which  is 
soft  and  malleable. 

152.  Float  a  sheet  of  sized  paj)er  on  an  NaCl  solution.  AVhen  drj',  float  it 
for  three  minutes  on  a  solution  of  AgNOj,  and  dry  in  the  dark.  Press  a 
fern-leaf  on  a  piece  of  glass,  lay  a  sheet  of  this  paper  on  it,  and  then  a  thin 
board  as  large  as  the  glass.  Clamp  them  together  with  clothes-pins,  and 
expose  to  direct  sunlight.  ^Vhcn  sufQciently  black,  place  in  a  solution  of 
"hypo,"  and  wash  thoroughly  with  water. 


DIKECTIONS     FOR     EXPERIMENTS.  285 


ORGANIC     CHEMISTRY. 

I  95 . — 153.  Dissolve  about  20  grams  of  grape-sugar  in  a  liter  of  water, 
and  put  tlie  solution,  with  a  little  yeast,  in  a  flask  connected  with  a  cylin- 
der or  bottle,  as  shown  in  Fig.  52,  A  and  B.  The  cylinder  JS  contains  some 
clear  lime-water,  and  the  end  of  the  short,  bent  tube  is  plugged  with  cotton 
to  prevent  the  air  from  entering  freely.  After  standing  some  hours  in  a 
warm  room,  B  wUl  contain  a  white  precipitate  of  CaCOa,  formed  by  the  CO2 
produced  by  the  fermentation.  The  contents  of  A  will  have  an  alcoholic 
odor,  and,  by  distilling,  a  dilute  alcohol  could  be  obtained. 

200. — 154.  Poxu"  a  little  alcohol  into  a  small  beaker,  and  suspend  over  it 
a  coil  of  Pt  wire,  which  has  been  heated  until  it  glows.  It  will  continue  to 
glow,  owing  to  a  slow  oxidation  of  the  alcohol  vapors.  The  peculiar  pene- 
trating odor  observed  is  due  to  aldehyde. 

155.  Another  instructive  experiment  by  which  aldehyde  is  produced  is  as 
follows :  Add  to  a  solution  of  potassium  bichromate,  sulphuric  acid  and  a 
little  alcohol.  On  heating,  the  odor  of  aldehyde  will  be  perceived,  while  the 
red  solution  becomes  green.    Explain. 

156.  Formic  acid  may  be  made  by  distilling  a  mixture  of  one  part  of  oxalic 
acid  and  ten  parts  of  glycerin.  The  dilute  acid  thus  obtained  may  be  used 
for  making  copper  formate :  Dissolve  in  the  acid  freshly  precipitated  and 
washed  copper  oxide  until  no  more  is  taken  up ;  filter  and  concentrate  the 
solution,  if  necessary,  by  evaporation,  when  copper  formate  will  separate  in 
beautiful  crystals. 

203.— 157.  Make  oxalic  acid  by  pouring  ordinary  strong  nitric  acid  upon 
sugar  (6  pts.  of  acid  to  1  of  sugar),  and  heating  gently  till  the  reaction 
begins.  The  sugar  is  oxidized  with  some  violence  and  evolution  of 
abundant  red  fumes.  On  cooling,  oxalic  acid  will  crystallize  out.  More 
can  be  obtained  by  evaporation.  Purify  the  acid  by  recrystallizing  it  from 
water. 

205. — 158.  Ether  may  be  made  by  heating  to  140°  C.  a  mixture  of  100 
grams  of  alcohol  and  180  grams  concentrated  sulphuric  acid.  The  operation 
should  be  conducted  in  a  retort  connected  with  a  cooler. 

206. — 159.  Mix  in  a  test-tube  equal  parts  of  acetic  acid  and  alcohol, 
and  add  a  little  concentrated  HaSOi.  The  odor  is  that  of  ethyl  acetate,  or 
acetic  ether. 

2  I  O.— 160.  Add  to  a  solution  of  sodium  carbonate  a  little  alcohol,  and 
then,  after  warming  it  to  about  80°  C,  introduce  gradually  a  few  crystals  of 
iodine.    Yellow  crystals  of  iodoform  will  separate  from  the  solution. 

2  I  9. — 161.  To  one  gill  of  water,  add  15  or  20  grains  of  strong  H^SO,. 
Place  in  a  large  flask,  and  heat.  While  boiling,  drop  in  slowly  two  drams 
of  starch,  finely  powdered.  Boil  for  several  hoiars,  adding  water  as  may  be 
necessary.  Finally,  drop  in  slowly  fine  chalk  until  the  liquid  is  neutral ; 
then  cool,  filter  off  the  calcium  sulphate.  The  solution  contains  grape- 
sugar.    Test  it  as  described  in  the  next  two  exp,eriments. 


286  DIRECTIONS     FOR     EXPERIMENTS. 

162.  Put  a  little  AgNOa  solution  in  a  test-tube,  and  add  aqua  ammonia 
slowly  until  the  brown  precipitate  has  again  dissolved.  Pour  some  of  this 
into  a  second  test-tube,  and  add  a  solution  of  grape-sugar.  On  boiling, 
the  silver  will  be  reduced  in  the  form  of  a  brilliant  mirror  on  the  side  of 
the  tube. 

163.  Take  a  solution  of  CuSO*,  and  add  enough  tartaric  acid  to  prevent 
its  being  precipitated  by  KOH.  Then  add  enough  KOH  solution  to  make 
it  strongly  alkaline.  Boil  this  solution,  and  add,  drop  by  drop,  a  dilute 
solution  of  grape-sugar.  The  intensely  blue  color  disappears,  and  a  red  pre- 
cipitate of  CU2O  is  produced.  This  is  called  Fehling's  test,  and  is  employed 
to  detect  sugar  in  diabetic  urine.  By  taking  proper  precautions,  the  amount 
of  the  sugar  may  be  accurately  determined. 

222.— 164.  Mix  together  in  a  test-tube  2  parts  of  HaSO,  and  1  part  of 
IINO3,  and,  when  cold,  allow  some  benzene  to  flow  into  it,  a  few  drops  at 
a  time,  waiting  each  time  till  the  reaction  is  complete,  and  keeping  the 
mixture  cool.  On  pouring  the  mixture  into  water,  it  will  be  found  that  the 
benzene  no  longer  floats  on  water  as  before,  and  has  acquired  a  very 
agreeable  odor.  An  atom  of  H  has  been  replaced  by  NO5,  forming  nifro- 
benzene,  C0H5NO2.     The  vapor  of  the  nitro-benzene  should  not  be  inhaled. 

165.  Dissolve  a  little  aniline  in  water,  and  add  a  filtered  solution  of 
bleaching  powder.    A  purple  color  is  produced. 

237.— 166.  Make  a  dilute  solution  of  gelatin,  and  add  a  solution  of  tan- 
nic acid ;  a  leathery  precipitate  is  formed. 

240.— 167.  Fill  a  test-tube  one  third  full  of  fresh  milk,  and  add  an  equal 
volume  of  water,  then  a  little  acetic  acid  (or  rennet),  and  allow  it  to  stand 
a  short  time ;  filter  out  the  precipitate,  and  wash  with  water.  The  pre- 
cipitate consists  of  casein  and  fats.  The  filtrate  contains  sugar,  as  may  bo 
shown  by  its  reducing  action  on  an  alkaline  solution  of  tartrate  of  copper. 
Remove  the  precipitate  from  the  filter,  and  shake  it  up  in  a  test-tube  with 
ether.  This  dissolves  out  the  fat.  Pilter  again ;  let  the  filtrate  evaporate, 
and  the  fat  will  be  left  in  a  pure  state. 

168.  Evaporate  a  larger  portion  of  milk  to  dryness,  and  heat  until  the 
residue  is  quite  white.  Dissolve  in  water,  filter,  and  test  for  chlorides  with 
AgNO,. 

243.— 169.  Mix  intimately  10  grains  of  gelatin  with  50  grains  of  soda- 
lime,  and  heat  strongly ;  NH3  gas  will  be  evolved,  and  can  be  detected  by 
its  odor,  its  action  on  reddened  Utmus-paper,  and  by  fuming  with  HCl. 

250.— 170.  The  ordinary  photographic  process,  as  given  on  p.  171,  is  a 
good  illustration  of  the  power  of  the  sun's  rays. 

171.  Dissolve  1  gram  of  ammonia-citrate  of  iron  in  20  cc.  of  water ;  add 
to  it  20  cc.  of  a  solution  of  K,PoOy„  made  in  the  same  manner.  Keep  the 
mixed  solution  in  the  dark.  Float  a  sheet  of  white  paper  on  the  solution, 
and  allow  it  to  dry.  Cover  a  plate  of  glass  with  black  varnish,  and  before 
it  dries  write  upon  it  with  any  sharp-pointed  instrument.  When  perfectly 
dry,  place  it  over  a  sheet  of  the  prepared  paper,  and  expose  two  or  three 
hours  to  bright  sunlight.  Remove,  and  wash  well  in  cold  water.  You  will 
have  the  writing  in  blue  on  a  white  ground. 


DIRECTIONS     FOR     EXPERIMENTS.  287 

172.  Mix  together  equal  volumes  of  a  solution  of  gelatin  and  a  solution 
of  KjCraO,,  and  add  a  little  tincture  of  logwood.  Pour  it  into  a  flat  dish, 
and  float  upon  it  a  sheet  of  unruled  writing-paper,  and  dry  in  the  dark. 
Expose  under  a  negative  (p.  172),  or  fern  leaves,  to  direct  sunUght  for  an 
hour,  then  wash  thoroughly  with  warm  water.  Bichromated  gelatin  is 
rendered  insoluble  by  exposiire  to  sunlight.  This  principle  is  employed  in 
all  photo-engra\T.ng  processes. 

173.  Mix  together  equal  volumes  of  H  and  CI  in  the  dark,  fill  a  small 
glass  bulb,  and  throw  it  up  into  a  bright  beam  of  the  sun,  when  it  explodes 
loUh  violence.  Do  not  at  any  time  hold  the  bulb  in  the  hand,  or  place  it  within 
several  feet  of  the  eyes. 

174.  Plants  decompose  COj  in  the  sunlight.     (See  p.  89  and  Exp,  70.) 


QUALITATIVE    ANALYSIS 

FOR     BEGINNERS. 


[  The  following  pages  on  analysis  were  prepared  Ijy  Prof.  E.  J.  Hallock, 
Ph.D.,  of  Boston.] 

In  order  to  be  able  to  analyze  almost  every  inorganic  sub- 
stance met  with  in  the  arts,  or  sold  in  the  shops,  it  is  only 
necessary  for  the  student  to  familiarize  himself  with  the  reac- 
tions of  about  twenty-six  metals  and  a  dozen  acids.  To  be  able 
to  apply  these  tests  with  certainty,  in  all  cases,  and  to  know 
the  easiest  and  best  methods  of  dissolving  the  substance,  consti- 
tute a  qualitative  chemist. 

For  reasons  which  will  appear  farther  on,  metals  are  divided 
into  five  groups. 

The  First  Group  embraces  lead,  silver,  and  the  mercurous 
salts  of  mercury.  They  are  classed  together  because  they  are  the 
only  metals  which  are  precipitated  from  solution  by  hydrochloric 
acid.  The  student  should  take  a  solution  of  lead  nitrate,  Pb 
2NO3,  formed  by  dissolving  litharge  or  lead  in  nitric  acid,  or 
some  lead  acetate  solution  (see  page  164),  and  try  the  following 
tests,  making  a  note  of  his  results.  With  HCl  a  white  precipi- 
tate of  PbClg  is  formed.  This  precipitate  is  filtered  out  and 
washed.  It  dissolves  in  boiling  water,  and  crystallizes  from 
this  solution  on  cooling.  To  another  portion  of  the  solution  add 
H2SO4  ;  a  white  precipitate  of  PbSO^  is  produced,  which  is  insol- 
uble in  HgO.  To  a  third  portion  add  potassium  chromate, 
K2Cr04  ;  a  yellow  precipitate  is  formed.  To  another  portion  add 
KI ;  a  yellow  precipitate  is  again  produced,  but  it  dissolves  in 
boiling  water,  and  forms  beautiful  crystals  on  cooling. 

Repeat  each  of  these  tests  with  silver  nitrate,  AgNOa  (experi- 
ment 149).  The  precipitate  with  HCl  is  insoluble  in  IxiiliTis^  HoG, 
but  dissolves  in  NH^OH,  and  is  reprecipitated  by  HNO3.  With  KI 
a  yellowish-white  precipitate  is  formed. 


QUALITATIVE     ANALYSIS  289 

Repeat  with  mercurous  nitrate,  HgNOg,  made  by  the  action 
of  dilute  HNO3  on  an  excess  of  Hg,  in  the  cold.  "We  have  with 
HCl  a  precipitate  of  calomel  (HgCl),  (page  176),  which  is  insoluble 
in  HgO,  and  blackens  on  adding  NH^OH,  but  does  not  dissolve. 
KI  forms  a  greenish-yellow  precipitate. 

Separating  Metals  of  Group  I. — Mix  the  solutions  of  the 
three  metals,  and  add  HCl.  Filter,  and  boil  the  precipitate  in 
water;  filter  hot,  and  to  the  filtrate  add  K,Cr04.  The  yellow 
precipitate  proves  that  lead  is  present.  Boil  the  residue  in 
ammonia  and  filter;  to  the  filtrate  add  HNO3.  A  white  precipi- 
tate proves  silver  present.  The  black  insoluble  residue  is  a 
compound  of  mercury  (Hg^H,NCl). 

The  Second  Group  embraces  the  mercuric  salts  of  mercurj^ 
together  with  Pb,  Bi,  Cu,  Cd,  As,  Sb,  Sn,  Au,  and  Pt.  They  are  pre- 
cipitated from  acid  solutions  as  sulphides  by  passing  H^S  gas 
through  the  solution.  (See  experiment  103.)  Of  these  HgS,  PbS, 
61,83,  CuS,  and  CdS  are  insoluble  in  ammonium  sulphide, 
(NH4)2S,  and  constitute  the  first  division  of  this  group.  The 
sulphides  of  the  remaining  five  metals  are  soluble  in  (NH4),S,  * 
and  form  the  second  division. 

Pass  HgS  gas  into  a  solution  of  corrosive  sublimate  (HgCU) 
(page  176) ;  a  precipitate  is  formed  which  is  at  first  white,  then 
yellow,  red,  and  finally  black.  It  is  insoluble  in  (NH4)2S,  and  in 
HNO3.  It  dissolves  in  aqua  regia  and  gives  a  gray  precipitate 
with  an  excess  of  SnCL,.  Repeat  the  first  experiment  wath  some 
lead  solution ;  a  black  precipitate  is  formed,  soluble  in  boiling 
HNO3.  In  this  solution  a  white  precipitate  of  PbSO^  is  formed 
on  adding  HoSO^.  Add  a  few  drops  of  KI  solution  to  the  origi- 
nal solutions  of  HgCU,  and  Pb2N03 ;  in  the  former  case  the  pre- 
cipitate (Hgl,)  is  red,  in  the  latter  (Pblo)  it  is  yellow.  These 
tests   are   characteristic   of   the   metals   when   alone.     Pass   H,S 


*  (NH4)2S  is  prepared,  according  to  Freseniiis,  by  saturating  a  given 
volume  of  ammonia  solution  (specific  gravity  0.96)  with  HjS  gas,  and  add- 
ing to  it  an  equal  volume  of  the  ammonia.  The  solution,  which  is  at  first 
colorless,  soon  becomes  yellow  by  keeping,  or  may  be  at  once  converted 
into  the  yellow  sulphide  by  the  addition  of  sulphur.  It  should  yield  no 
precipitate  with  magnesium  sulphate  (Epsom  salt).  This  re-agent  is  decom- 
posed by  acids,  sulphur  being  precipitated. 


290  QUALITATIVE     ANALYSIS. 

into  BiSNOj  solution;*  a  black  precipitate  is  formed;  dissolve 
in  HNO3  ;  add  a  drop  of  HoSO^  to  prove  it  is  not  lead;  then 
cautiously  add  ammonia,  which  produces  a  vrhite  precipitate  of 
Bi(0H)3.  Repeat  all  the  above  experiments  vi^ith  CdSO^  solution; 
the  precipitate  with  H,S  is  a  beautiful  yellow,  soluble  in  HNO,, 
but  insoluble  in  KCy.  Pass  HoS  in  CuSO^  solution,  and  a 
brownish-black  precipitate  will  be  formed,  soluble  in  HNO,  and 
in  KCy.  Salts  of  copper  have  a  bluish  color,  which  becomes 
more  intense  on  adding  NH^HO.  {Experiment  141.)  "With 
potassium  ferrocyanide  (Kj(FeCy6)  they  give  a  reddish-brown  pre- 
cipitate insoluble  in  HCl. 

Separating  Metals  of  Second  Group,  First  Division.— After 
the  student  has  made  all  the  above  reactions  he  may  mix  the 
solutions  of  the  five  metals  and  proceed  to  separate  them.  Some 
of  the  lead  is  precipitated  by  HCl,  and  is  filtered  out  before  HgS 
is  passed  through  the  solution.  The  precipitate  with  H^S  is 
boiled  in  HNO3,  and  HgS  remains  as  a  residue.  When  the  origi- 
nal solution  was  very  acid,  S  will  be  found  mixed  \\ath  HgS  in 
the  residue  insoluble  in  HNO3.  To  the  filtrate  add  a  little  HoSO^  to 
precipitate  the  lead  present;  filter  from  the  PbSO^  and  add 
NH4OH  ;  B1(0H)3  is  precipitated.  The  precipitate,  dissolved  in 
aqua  regia  and  concentrated  by  evaporation,  should  give  a  white 
precipitate  if  poured  into  water.  The  addition  of  NH^Cl  aids 
this  reaction.  The  blii£,  filtrate  from  the  Bi  precipitate  is  boiled 
with  KCy,  care  being  taken  not  to  inhale  the  fumes,  and  HjS 
added ;  CdS  forms  a  yellow  precipitate.  The  presence  of  Cu  in 
the  filtrate  from  CdS  is  proved  by  the  formation  of  a  reddish- 
brown  precipitate  with  K4FeCy6,  after  HNO,  has  been  added  to 
the  solution. 

The  most  interesting  metal  of  group  second,  second  division, 
is  As.  HjS  in  an  HCl  solution^f  Asj03  gives  a  yellow  precipitate 
As.Sg  ;  it  is  soluble  in  (NH4)2S,  and  in  (NH4)X03.  The  neutral 
salts  of  arsenious  acid  yield   with  AgNOj,  a  yellow  precipitate, 

♦  "WTieii  Bi  solutions  are  diluted  with  water,  basic  salts  are  precipitated 
unless  there  be  much  free  acid  present.  This  reaction  is  most  sensitive 
with  BiCls,  so  that  HCl  may  be  used  to  dissolve  the  BiSNOs  for  the  HjO 
toet. 


QUALITATIVE     ANALYSIS.  291 

AgjAsOg,  soluble  in  HNO3.  A  small  piece  of  bright  green  paper 
often  contains  enough  of  this  metal  to  give  several  characteristic 
tests.  Apply  a  single  drop  of  nitric  acid  to  the  paper  ;  a  moment 
after  neutralize  with  ammonia  and  observe  the  color,  a  deep 
blue  always  indicating  copper.  When  the  white  fumes  have 
nearly  disappeared,  apply  to  the  same  spot  a  drop  of  AgNOg  ;  a 
yellow  ring  indicates  As.  The  most  delicate  test  for  As  as  well  as 
Sb  is  Marsh's  test  (see  page  119).  The  mirror  formed  by  As  on 
porcelain  is  soluble  in  sodium  hypochlorite  (Labarraque's  solution); 
that  of  Sb  is  insoluble  in  this.  If  AsHj  is  passed  into  AgNOa, 
metalHc  Ag  is  precipitated  and  enough  HNO3  is  set  free  to  keep 
the  As  in  solution  until  it  is  carefully  neutralized  with  NH^OH, 
when  a  precipitate  of  AgjAsOa  appears. 

Antimony  closely  resembles  As  in  its  reactions.  Pass  HoS 
into  a  solution  of  tartar  emetic  {experiment  103),  and  an  orange- 
colored  precipitate,  SbaSg,  will  be  formed,  soluble  in  (NH4)2S, 
and  re-precipitated  on  adding  dilute  HCl  to  this  solution.  This 
precipitate  is  soluble  in  strong  HCl,  while  the  corresponding 
arsenic  precipitate  is  not.  Put  some  of  the  Sb  solution  in  a  new 
Marsh's  apparatus.  The  mirror  is  insoluble  in  sodium  hypo- 
chlorite. 

Tin  dissolves  in  HCl,  but  is  oxidized  to  a  white  powder  by 
HNO3  without  dissolving.  There  are  two  series  of  tin  salts  ;  SnCU 
gives  a  dark  brown  precipitate  with  H^S  ;  SnCl4  a  yellow  pre- 
cipitate with  HgS,  both  soluble  in  yellow  (NH4)3S.  SnCU  forms 
with  an  excess  of  HgCU,  a  white  precipitate  of  HgCl ;  but  when 
SnClo  is  in  excess  a  gray  precipitate  of  Hg  is  formed.  On  adding 
dilute  HCl  to  the  (NH4),S  solution  of  the  sulphide,  it  is  re-pre- 
cipitated yellow,  even  though  it  may  have  been  brown  before  it 
was  dissolved.     It  dissolves  in  strong  HCl. 

Gold  and  platinum  are  distinguished  from  all  other  metals  by 
their  insolubility  in  HCl  or  HNO3,  but  are  converted  into  soluble 
chlorides  by  aqua  regia.  The  characteristic  test  for  Au  salts  is 
SnClo  mixed  with  SnCl^,  the  purple  of  Cassius  being  formed. 
PtCl4  will  give  a  yellow  precipitate  with  NH4CI  and  alcohol, 
(NHJ.PtCle. 

Separating  Metals  of  Second  Group,  Second  Division. — Into 
an  acid  solution  of  Sn,   Sb,   and  As,  pass   HgS  gas.      Filter  and 


292  QUALITATIVE     ANALYSIS. 

dissolve  precipitate  in  (NH4)2S  to  remove  any  members  of  first 
division,  if  these  are  to  be  looked  for.  Re-precipitate  the  sul- 
phides with  dilute  HCl,  filter  and  wash.  Then  treat  with  strong 
hot  HCl  ;  if  a  residue  remains  it  is  probably  As^Sj.  Dissolve 
this  in  HCl  with  the  aid  of  a  little  solid  KCIO3,  and  test,  as  de- 
scribed in  experiment  110,  or  in  Marsh's  apparatus.  The  filtrate 
from  AsoSj  contains  Sb  and  Sn.  Put  this  in  another  Marsh's 
apparatus  ;  the  mirror  will  be  insoluble  in  hypochlorites.  When 
the  zinc  has  all  dissolved,  take  the  residue  and  dissolve  it  in 
HCl  and  test  for  Sn  with  HgCl,. 

As  Au  and  Pt  are  seldom  to  be  sought  for,  this  part  of  the 
separation  may  be  omitted.  The  mixed  sulphides  of  Au,  Pt,  As, 
Sb,  and  Sn  may  all  be  placed  in  Marsh's  apparatus,  as  directed 
in  the  table  on  page  302,  when  the  As  and  Sb  combine  with  H, 
and  are  separated  by  passing  the  AsHg  and  SbHg  into  AgNOj. 
The  metallic  Sn,  Au,  and  Pt  remain  in  the  H  generator ;  the  Sn 
is  then  dissolved  out  with  HCl,  and  tested  with  HgClj,  ;  the  Au 
and  Pt  are  dissolved  in  aqua  regia  and  tested  in  separate  portions 
of  the  solution,  as  described  above. 

Group  Third  embraces  Co,  Ni,  Fe,  Cr,  Mn,  Al,  and  Zn.  They 
are  precipitated  by  (NH^)3S  from  neutral  or  alkaline  solutions. 
The  characteristic  test  for  Co,  is  the  blue  color  imparted  to  a 
borax  bead.  Nl  alone  gives,  in  the  outer  blow-pipe  flame,  a  reddish- 
brown  bead,  in  the  inner  gray.  Both  give  with  (NH4)2S  black 
precipitates  insoluble  in  dilute  HCl.  If  KNOg  and  acetic  acid  are 
added  to  a  solution  of  Co  and  Nl,  the  former  is  slowly  precipitated 
and  not  the  latter.  To  a  solution  of  FeS04,  add  a  drop  of  potas- 
sium ferricyanide  (KjFeCyg);  a  blue  precipitate  is  formed.  To 
another  portion  add  (NH4)„S  ;  a  black  precipitate  is  formed,  soluble 
in  dilute  HCl,  from  which  solution  it  is  re-precipitated  by  NaOH, 
as  greenish  Fe(OH)o.  Repeat  the  latter  test  with  ferric  chloride 
(FegClg)  and  reddish  brown  Fe2(0H)g  is  precipitated.  FegClg  gives 
with  K^FeCyg  a  precipitate  of  Prussian  blue.  In  a  glass  of  water 
place  one  drop  of  Fe„Cl«,  and  add  a  few  drops  of  potassium 
sulphocyanide  (KCyS) ;  the  liquid  acquires  a  blood-red  color.  Iron 
salts  also  give  characteristic  colors  to  the  borax  beads ;  yellow 
in  the  outer  and  green  in  the  inner  flame.  To  a  solution  of  MnSO^, 
add  (NH^jgS  ;  a  tlesh-coloi'ed  precipitate  is  formed,  soluble  in  HCl; 


QUALITATIVE     ANALYSIS.  293 

NaOH  precipitates  Mn(0H)3.  The  borax  bead  with  Mn  acquires 
an  amethyst-red  color  (see  note,  page  122)  in  the  outer  blow-pipe 
flame.  Fused  with  NayCOg  and  KNO3  a  green  mass  is  formed. 
(NH^)aS  gives  with  the  salts  of  Cr,  a  greenish  precipitate  of 
Cr2(0H)e,  soluble  in  HCl,  and  re-precipitated  when  boiled  with  NaOH. 
Pused  with  Na^COj  and  KNO3  it  forms  yellow  potassium  chromate 
K2Cr04.  "When  this  is  dissolved  in  water  and  acidified  with  acetic 
acid,  it  yields  a  yellow  precipitate  with  PbSNOj.  To  a  solution 
of  alum  add  (NH4)^S;  it  forms  a  white  precipitate  soluble  in 
dilute  HCl.  To  the  second  portion  add  NH^OH,  a  white  precipitate; 
and  to  a  third  add  NaOH  and  boil;  the  white  precipitate  at  first 
formed  dissolves  again.  To  a  solution  of  ZnS04,  obtained  in 
experiment  30,  add  NH^OH  slowly.  The  white  precipitate  at 
first  formed  dissolves  when  more  NH4OH  is  added.  In  this  solu- 
tion HjS  causes  a  white  precipitate  of  ZnS. 

Separation  of  Metals  of  Group  Third. — Some  NH^Cl  and 
NH4OH  is  first  added;  then  (NH4)gS.  The  precipitate  is  digested 
in  dilute  HCl;  Nl  and  Co  are  sought  in  the  residue.  The  filtrate 
is  boiled  with  NaOH  for  half  an  hour  in  a  porcelain  dish,  and 
filtered.  To  the  filtrate  HCl  is  added  until  acid,  then  NH^OH, 
which  precipitates  Al ;  Zn  is  precipitated  from  the  filtrate  from 
this  by  HgS  or(NH4)gS.  The  residue,  containing  Fe,  Mn,  and  Cr,  is 
fused  with  pure  KNO3  and  NaoCOj  ;  if  the  mass  is  green,  Mn  is 
indicated ;  if  yellow,  Cr.  One  half  of  the  mass  is  warmed  with 
water ;  the  insoluble  residue  is  tested  for  iron ;  the  filtrate  is 
tested  for  Cr  by  first  neutralizing  with  acetic  acid,  and  then  add- 
ing Pb2N03.  The  test  for  Mn  is  to  boil  some  of  the  fused  mass 
in  HNO3,  with  red  lead;  a  beautiful  rose  pink  is  produced  from 
the  formation  of  KMnO^. 

Group  Fourth  embraces  the  metals  of  the  alkaline  earths, 
Ba,  Sr,  and  Ca,  whose  carbonates,  precipitated  by  (NH  4)2003,  are 
insoluble  in  H^O,  but  soluble  in  acetic  acid  or  in  HCl.  BaCl^ 
forms  with  Ho  SO  4  or  a  clear  solution  of  CaSOi,  a  precipitate  in- 
soluble in  acids;  KoCr04  precipitates  yellow  BaCr04.  Ba  com- 
pounds impart  a  green  color  to  the  flame  of  an  alcohol  lamp  or 
Bunsen  burner.  CaCU,  with  ammonium  oxalate,  yields  a  white 
precipitate  insoluble  in  acetic  acid.  H2SO4  produces  a  white 
precipitate   of   CaS04,  slightly  soluble  in  water  and   acids.      Ca 


294  QUALITATIVE     ANALYSIS. 

salts  color  the  flame  yellowish  red.  SrClg  gives  a  white  precipi- 
tate with  a  clear  solution  of  CaS04  ;  if  the  solution  is  dilute, 
half  an  hour  is  required  for  the  precipitation.  Sr  colors  the 
flame  crimson-red. 

Separating  Metals  of  Group  Fourth. — Some  NH4CI  is  first 
added,  if  not  already  present  in  the  solution,  then  (NH4)2C03.' 
The  precipitate  is  dissolved  in  acetic  acid,  and  divided  in  two 
portions.  To  one  is  added  KjCr04  ;  Ba  is  precipitated  yellow, 
and  the  filtrate  is' tested  for  Sr  by  means  of  CaSO^.  Ho  SO  4  is 
added  to  the  other  portion,  the  precipitate  filtered  out.  NH4OH 
is  added  to  the  filtrate,  which  is  now  tested  for  Ca  with  am- 
monium oxalate. 

Group  Fifth  embraces  Mg,  K,  Na,  and  LI.  As  lithia  is  very 
rare,  we  omit  its  reactions.  MgS04  yields  a  white  precipitate  of 
Mg(0H')2  on  the  addition  of  NH4OH,  unless  the  solution  contains 
NH4CI;  hence  the  necessity  of  adding  NH4CI,  before  testing  for 
groups  III.  and  IV.,  where  NH4OH  would  otherwise  throw  down 
Mg.  The  salts  of  Mg  give  a  white  precipitate  with  sodium 
phosphate,  Na,HP04,  and  NH4OH.  KCl  yields  a  yellow  precipi- 
tate with  PtCl4  ;  Potassium  tartrate  is  precipitated  from  con- 
centrated solutions  by  sodium  tartrate.  K,S04  gives  a  white 
precipitate  with  2HF,SiF4  and  alcohol.  K  imparts  a  violet  color 
to  flame,  which  appears  reddish  violet  when  viewed  through 
blue  glass.  Na  is  not  precipitated  by  any  of  the  above  re- 
agents ;  it  imparts  an  intense  yellow  color  to  flame.  K,  Na,  and 
LI,  as  well  as  Ca,  Ba,  and  Sr,  are  easily  detected  by  the  spectro- 
scope. 

Ammonia  is  liberated  from  its  compounds  by  heating  with 
NaOH  or  Ca(OH)j,  and  is  then  recognized  by  the  smell,  by  bluing 
red  litmus,  and  by  producing  white  fumes  when  a  rod  moistened 
with  HCl  gas  is  held  over  it.    (See  page  35.) 


TESTS     FOR     ACIDS. 

The  acids  do  not  admit  of  the  strict  grouping  and  successive 
separation  employed  for  metals,  and  we  will  rest  content  with 
mentioning  the  simplest  tests  for  the  principal  acids,  beginning 
with  those  of  the  halogens : 


QUALITATIVE     ANALYSIS.  295 

HCl  with  AgNOa,  white  precipitate,  soluble  in  NH^OK,  not  in 
HNO3. 

HI  with  AgNOg,  yellowish  precipitate,  almost  insoluble  in 
NH4OH. 

HI  with  HgCl,,  red  precipitate,  soluble  in   KI. 

HI  with  starch  paste  and  CI  solution  or  bleaching  powder, 
blue  color.     (See  page  101.) 

CaFj  with  H2SO4  liberates  HF,  which  attacks  glass.  (See  page 
102.) 

HBr  with  starch  paste  and  CI  water,  an  orange-yellow  color. 

HoSO^  with  BaClo,  white  precipitate,  insoluble  in  HCl. 

SlOg  is  insoluble  in  HgO,  as  are  most  of  the  silicates  except 
those  of  K  and  Na.  In  analyzing  the  soluble  silicates,  they  are 
first  evaporated  to  dryness  with  excess  of  HCl,  the  soluble  chlo- 
rides dissolved  in  HoO  or  HCl,  and  the  SlOo  left  as  a  gritty  pow- 
der. 

Boric  Acid  is  detected  by  placing  it  in  a  dish  containing  alco- 
hol and  H2SO4,  and  igniting  the  alcohol.  A  green  tinge  to  the 
flame  indicates  B.  If  a  mixture  of  glycerin  and  borax  is  brought 
into  a  flame  and  removed  as  soon  as  it  takes  fire,  the  green 
flame  is  easily  recognized.    (Experiments  112  and  113.) 

H3PO4  with  neutral  AgNOj,  yellow  precipitate,  soluble  in  HNO3 
and  NH.OH. 

H3PO4  with  solution  of  ammonium  molybdate  in  HNO3,  a  fine 
yellow  precipitate. 

H3PO4  with  MgS04  solution  containing  NH4CI  and  NH4OH,  a 
white  precipitate  soluble  in  acids.     (See  test  for  Mg,  page  294.) 

CO,.  Carbonates  effervesce  on  the  addition  of  acids,  COg  being 
set  free,  which  extinguishes  a  match  inserted  in  the  test-tube. 
The  ear  is  often  able  to  detect  slight  effervescence  not  otherwise 
perceptible. 

HNO3  is  not  precipitated  by  any  re-agent.  Into  a  test-tube 
containing  some  nitrate,  drop  a  crystal  of  FeS04,  then  allow  a 
few  drops  of  HgSO^  to  flow  down  the  side  of  the  test-tube  which 
is  held  inclined.  A  characteristic  dark-brown  ring  forms  imme- 
diately. If  Cu  and  strong  H0SO4  are  heated  with  a  nitrate,  red 
fumes  are  given  off.     A  nitrate  heated  on  charcoal  deflagrates. 

Chlorates  deflagrate  more  violently  than  nitrates.  H2SO4  lib- 
erates CI3O4,  which  is  betrayed  by  its  color  and  odor.     If  a  crys- 


296  QUALITATIVE     ANALYSIS. 

tal  of  KCIO3  and  a  piece  of  P  be  placed  in  a  glass  of  water,  and 
a  drop  of  H^,S04  conveyed  to  it  by  a  pipette  or  tube,  the  P  takes 
fire  and  burns  under  water  (page  131).  All  experiments  with 
chlorates  must  be  performed  with  minute  quantities,  because  of 
the  great  danger  of  explosions. 

SO,  is  easily  recognized  by  its  odor.  When  sulphites  are 
treated  with  HCl,  the  SO,  is  evolved. 

If  CI  gas  be  given  off  on  heating  a  substance  in  HCl,  the 
presence  of  a  binoxide  may  be  suspected.    (See  page  92.) 

If  an  odor  of  H^S.  is  perceived  on  treating  a  substance  with 
HCl,  it  is  evidently  a  sulphide.  Heated  with  strong  HNO3,  sul- 
phides are  converted  into  sulphates. 

HCy  with  AgNOg,  white  precipitate  soluble  in  KCy ;  difficultly 
soluble  in  NH4OH.  Care  must  be  taken  in  handling  the  poison- 
ous cyanide.  On  adding  HCl  to  a  cyanide,  HCy  is  liberated,  and 
is  detected  by  the  odor,  which  resembles  bitter  almonds. 

H^FeCyg  with  AgNOg,  white  precipitate  insoluble  in  NH^OH,  and 
in  HNO3.     With  Fe^Clg,  Prussian  blue  [Fe4(FeCye)j]  is  formed. 

Oxalic  Acid,  HaC^O^,  jaelds  a  white  precipitate  with  CaCL, 
which  is  insoluble  in  acetic  acid. 

When  several  acids  are  present  they  are  tested  for  in  separate 
portions.  AS3O3  may  occasionally  be  mistaken  for  H3PO4.  BaCl, 
will  yield  precipitates  with  carbonic,  oxalic,  phosphoric,  and  sul- 
phuric acids,  but  they  all  dissolve  in  HCl  except  BaS04. 

To  test  for  HCl  in  the  presence  of  HI,  or  HBr,  or  both,  the  dry 
powder  is  mixed  with  dry  K^CroOj,  and  pure  concentrated  HjSO^ 
added,  and  heated,  when  CrOoCL,  is  given  off  as  a  brownish-red 
gas;  and  a  glass  rod  dipped  in  NH^OH  and  held  over  the  tube 
becomes  slightly  yellow  if  CI  is  present,  from  the  formation  of 
(NH4),Cr04.  If  the  substance  to  be  tested  contains  only  Br  and  I, 
these  two  may  be  separated  by  CUSO4  and  H^SOj,  which  precipi- 
tates the  latter  as  Cu^L  and  permits  the  use  of  the  starch  test 
for  Br.  Or  chloroform  is  added  to  the  solution  and  a  very  little 
CI  water,  or  solution  of  bleaching  powder,  is  then  poured  in  and 
the  test-tube  well  shaken.  Then  I  is  liberated  and  dissolved  by 
the  chloroform,  imparting  to  it  the  well-known  purple  color,  the 
intensity  of  which  conceals  the  yellowish-brown  color  of  the  Br 
likewise  set  free  and  dissolved.  On  adding  more  CI  water,  the 
violet  disappears,  leaving  only  the  yellow  color  due  to  the  Br. 


QUALITATIVE     ANALYSIS.  297 


PRELIMINARY     TESTS. 

A  few  tests  in  a  dry  way  will  give  some  clew  to  the  sub- 
stances present ;  but  in  a  complete  analysis  every  acid  and  every 
metal  must  be  sought  for. 

I.  Heating  in  a  Tube  of  Hard  Glass  closed  at  one  end. — 
If  the  substance  blackens,  organic  matter  is  probably  present. 
If  vapors  escape,  thej^  are  tested  for  CO2,  SO,,  HoS,  etc.  If  a 
sublimate  is  formed,  it  may  be  S,  I,  Hg,  a  compound  of  Hg,  As, 
Sb,  or  a  salt  of  ammonium. 

II.  Heating  on  Charcoal. — A  small  portion  of  the  substance 
is  placed  on  charcoal  and  exposed  to  the  inner  blow-pipe  flame. 
(See  page  83.)  If  an  infusible  white  residue  remains,  moisten  it 
with  C02NO3  and  heat  it  again ;  a  fine  blue  indicates  Al,  a  phos- 
phate or  SiO,,  a  reddish  tint  Mg,  a  green  color  Zn.  Mix  another 
portion  with  Na^COg  and  heat  on  charcoal  in  the  reducing  flame. 
If  a  metallic  globule  is  formed  without  an  incrustation,  it  indi- 
cates Au,  Cu,  or  Ag,  as  the  color  is  yellow,  red,  or  white.  A  very 
fusible  and  malleable  globule  surrounded  by  a  yellow  incrusta- 
tion indicates  Pb  ;  if  the  incrustation  is  white  it  may  be  Sb  or  Sn  ; 
if  orange,  yellow  while  hot,  becoming  lighter  on  cooling,  B!.  The 
globules  of  Sb  and  Bi  are  hard  and  brittle.  If  As  is  present,  an 
odor  resembhng  garhc  is  noticed.  The  charcoal  tests  will  be  of 
little  use  to  the  student,  except  for  detecting  Ag  and  Pb,  until  prac- 
tice has  given  him  considerable  facility  in  the  use  of  the  blow-pipe. 

III.  Borax  Beads. —  Several  metals  impart  characteristic 
colors  to  borax  glass  when  fused  with  it  before  the  blow-pipe. 
The  end  of  a  piece  of  platinum  wire  is  bent  to  form  an  eye  as 
large  as  this  letter  O  ;  it  is  next  dipped  in  borax  and  held  in  the 
flame  until  fused,  then  dipped  in  the  powdered  substance  and 
fused  again.  The  color  varies  according  as  the  oxidizing  or 
reducing  flame  is  employed. 

Color.  Oxidizing.  Reducing. 

Blue Co  and  Cu  Co 

Green Cr  and  Cu  Fe  and  Cr 

Red Fe   and  Ni  Cu  (opaque) 

Amethyst Mn  

Yellow  to  brown Fe  

Colorless SI,  etc.  Mn 

Gray Ni 


298  QUALITATIVE     ANALYSIS. 


SOLUTION. 

The  first  thing  to  be  done  before  beginning  an  analysis  is  to 
bring  the  substance  into  solution.  Distilled  water'  is  first  em- 
ployed ;  if  a  residue  insoluble  in  water  remains,  it  is  treated  with 
acid.  In  analyzing  metals  and  alloys,  nitric  acid  is  the  usual 
solvent ;  aqua  regia  being  required  only  for  the  noble  metals. 
If  Sn  is  present,  and  Pb  and  Ag  absent,  HCl  is  employed.  Min- 
eral substances,  if  insoluble  in  any  acid,  are  rendered  soluble  by 
fluxing,  or  fusing  with  pure  Na^COa  and  KjCOg.  As  a  very  high 
heat  is  required  for  fluxing,  deflagration  is  sometimes  preferred. 
One  part  of  the  insoluble  powder  is  intimately  mixed  with  two 
parts  of  dry  sodium  carbonate,  two  parts  pulverized  charcoal, 
and  twelve  parts  niter.  The  mixture  is  placed  in  the  open  air 
and  a  match  applied.  A  portion  of  the  porous  mass  produced 
will  be  soluble  in  water,  the  remainder  in  acids.  The  two  solu- 
tions are  to  be  preserved  and  tested  separately.  The  metals  will 
be  found  in  the  acid  solution,  while  the  acids  will  be  found  in 
the  aqueous  solution.  Before  beginning  the  regular  course  of 
analysis  with  these  solutions,  part  of  the  aqueous  solution  is 
evaporated  to  dryness  with  excess  of  HCl  to  render  all  the  SiO, 
insoluble.  In  separate  portions  of  the  aqueous  solution,  the 
various  acids  are  sought  as  above  described  (p.  294). 

If  a  portion  of  the  substance  is  insoluble  in  HCl  after  fluxing, 
it  is  probably  silicic  acid,  or  an  undecomposed  silicate,  and  may 
be  rendered  soluble  by  fluxing  a  second  time. 

A  platinum  crucible  must  never  be  employed  if  reducible 
metals,  especially  Pb,  As  or  Sb  have  been  found  in  the  prelim- 
inary tests. 

EXAMPLES     FOR     PRACTICE. 

After  the  student  has  made  all  the  tests  above  given,  and 
succeeded  in  separating  the  members  of  each  group  from  each 
other,  especial  care  being  given  to  the  separation  of  lead  from 
bismuth,  copper  from  cadmium,  arsenic  from  antimony,  and 
nickel  from  cobalt,  the  teacher  may  give  out  the  following  or 
similar  substances  for  analysis,  not  following  the  precise  order 
of  the  book,  so  that  the  student  shall  not  know  what  substance 


QUALITATIVE     ANALYSIS. 


299 


he  is  analyzing.  Each  student  should  record  the  results  of  every 
analysis  in  a  note-book  which  he  will  rule  for  each  analysis  as 
shown  under  No.  1. 

1.  Analysis  of  CUSO4. — A  crystal  of  this  salt  as  large  as  a 
pea  is  given  to  a  student,  who  dissolves  it  in  distilled  water  in 
a  test-tube  and  divides  the  solution  in  two  portions.  To  one  is 
added  a  drop  of  HCl,  which  should  produce  no  precipitate.  H^S 
is  then  added  until  all  the  Cu  is  precipitated.  The  solution  is 
then  filtered  and  the  precipitate  thoroughly  washed  on  the  filter. 
HgS  should  produce  no  precipitate  in  the  filtrate.  The  precipitate, 
which  is  found  to  be  insoluble  in  (NIH4)2S,  is  dissolved  in  HNO3, 
and  no  residue,  except  perhaps  a  little  sulphur,  remains,  so  that 
the  absence  of  Hg  is  established.  HoSO^  produces  no  precipitate 
in  this  solution,  hence  Pb  is  absent.  Ammonia,  added  in  excess, 
gives  no  precipitate  (Bi  is  absent),  but  the  intense  blue  color  char- 
acteristic of  Cu,  and  as  only  one  metal  is  to  be  sought,  the  pres- 
ence of  Cu  is  further  proved  by  adding  HNO3  and  K^FeCyg,  which 
causes  a  reddish-brown  precipitate.  The  second  portion  of  the 
solution  is  used  in  testing  for  acids.  To  a  small  quantity  of  this 
some  BaClj  is  added,  and  if  the  precipitate  is  insoluble  in  HCl, 
the  acid  present  must  be  HoSO^.  The  results  are  recorded  in 
tabular  form  thus : 


ANALYSIS   NO.    1. 
Substance  Blue,  Soluble  in  HjO. 


GROUP  I. 

GROUP  II. 

GROUP  III. 

GROUP  IV. 

GROUP  V. 

HCl 

HgS 

(NH,)3S 

(NHJ^CO, 

0 

Brown     pre- 
cip.,  sol.  in 
HNO3. 

NH^OH  blue. 

K.FeCye 
brown. 

Cu. 

0 

0 

0 

Acids:   BaClg  ;  White  precipitate  insol.  in  HCl 


HoSO^. 


300  QUALITATIVE     ANALYSIS. 

2.  Analysis  of  HgCl^. — This  salt  is  likewise  very  soluble  in 
HgO.  To  one  portion  of  the  solution  add  HCl,  and  HoS.  The  lat- 
ter produces  a  black  precipitate,  insoluble  in  HNO^,  which  indi- 
cates Hg,  but  a  confirmatory  test  must  be  employed,  which  is 
to  dissolve  the  precipitate  in  aqua  regia  and  add  SnCU.  To  a 
second  portion  add  some  BaCU,  which  will  cause  no  precipitate. 
To  a  third  portion  add  AgNOj,  which  produces  a  white  precipi- 
tate, insoluble  in  HNO3,  but  soluble  in  NHjOH,  proving  the  pres- 
ence of  HCl. 

3.  Analysis  of  FeSO^. — Acidify  a  portion  of  the  solution  with 
HCl,  add  a  little  HoS  to  prove  that  no  metals  of  the  second  group 
are  present,  and  then  (NH4),S,  which  produces  a  black  precipi- 
tate, which  is  treated  as  directed  for  Group  III.,  page  293.  To 
some  of  the  original  solution  a  drop  of  KgFeCye  is  added,  when 
the  blue  color  proves  the  presence  of  Fe. 

4.  Analysis  of  Sr2N03. — Dissolve  in  water,  test  for  Groups 
I.,  II.,  and  III.,  which  may  occur  as  impurities,  and  then  add 
(NH4)2C03.  The  white  precipitate  is  filtered  out  and  washed,  then 
dissolved  in  acetic  acid.  To  one  portion  add  KgCr04,  when  the 
absence  of  Ba  is  shown,  and  the  Sr  test  may  next  be  made,  by 
adding  NH^OH  and  CaSO^.  The  precipitate  forms  slowly.  In 
the  original  solution  no  precipitate  is  formed  by*  BaCU  or  AgNOj, 
and  a  careful  test  for  HNO3  is  made. with  FeS04  and  H0SO4,  as 
described  on  page  295. 

5.  Analysis  of  BaSO^,.— This  substance  refuses  to  dissolve 
either  in  H,0  or  in  acids.  It  is  boiled  repeatedly  with  fresh 
quantities  of  NaoCOa  and  filtered  boiling  hot ;  or  fluxed  with  KNO3 
and  Na.COg.  The  filtrate  contains  Na^SO^  ;  the  residue  is  BaCOg 
(and  unaltered  BaSO^).  The  residue  is  dissolved  in  HCl  and  tested 
for  Ba  with  K2Cr04  or  SrS04  solution. 

6.  Analysis  of  a  Coin. — A  silver  coin  is  dissolved  in  HNO3, 
then  diluted  and  the  Ag  precipitated  with  HCl  as  AgCl.  From  this 
metallic  silver  is  precipitated  on  a  piece  of  clean  zinc  placed  in  the 
precipitate,  which  is  moistened  with  dilute  H0SO4.  In  the  blue 
filtrate  will  be  found  all  the  copper,  which  may  be  tested  for  as 
above.  If,  instead  of  a  silver  coin,  a  nickel  coin  is  used.  HCl  will 
give  no  precipitate,  the  Cu  will  be  thrown  down  by  HgS,  and  the 
Ni  by  (NH4)3S.  In  analyzing  compound  substances,  great  care 
must  be  taken  that  all  the  metals  of  a  certain  group  are  precipi- 


QUALITATIVE     ANALYSIS.  301 

tated  before  proceeding  to  the  next,  and  for  this  purpose,  after 
precipitating  the  Ag  with  HCl,  a  drop  of  HCl  is  added  to  the  filtrate 
to  ascertain  whether  any  Ag  remains  in  solution.  Precipitates 
should  also  be  well  washed,  but  the  wash-water  is  not  added 
to  the  filtrate. 

7.  Analysis  of  Mixed  Salts. — A  mixture  of  Pb2N0a,  BI3NO3, 
CoSNOg,  KNO3  may  be  dissolved  in  water  and  the  metals  sought 
in  the  above  order  (viz.  Pb,  Bi,  Co,  K).  In  testing  for  acids  the 
student  will  remember  that  if  Pb  was  found  among  the  metals, 
H2SO4  and  HCl  must  have  been  absent,  as  either  would  have  pre- 
cipitated the  lead.  If  the  student  forgets  this  and  adds  BaCU  to 
the  solution,  it  will  form  a  precipitate  of  PbCL,  which  he  might 
mistake  for  BaSO^,  and  hence  incorrectly  suppose  HgSO^  to  be 
present. 

Mixtures  of  various  other  soluble  salts  should  now  be  given 
out,  such  as  FeSO^,  NaCl,  CuSO^,  and  NH^Cl;  gradually  increasing 
t^ie  number  of  metals  and  acids  to  be  sought. 

8.  Analysis  of  Lime-stone. — Dissolve  any  piece  of  marble  or 
lime-stone  in  HCl.  It  will  not  be  necessary  to  test  for  groups  I. 
and  II.;  a  small  portion  of  the  solution  is  tested  with  K4FeCy6  for 
iron.  The  alumina  generally  present  is  precipitated,  along  with 
the  iron,  by  NH4OH,  after  adding  NH4CI,  and  is  filtered  out  as 
rapidly  as  possible.  In  a  small  portion  of  the  filtrate  tests  are 
made  for  Ba  and  Sr,  which  are  of  course  absent,  so  that  all  the  Ca 
may  be  precipitated  by  oxalate  of  ammonia.  In  the  filtrate  Mg 
will  be  found  on  adding  NagHPO^.  The  principal  acid  present 
is  CO,,  as  indicated  by  the  effervescence  with  HCl  when  first 
dissolved.  If  a  residue  remained  insoluble  in  HCl,  it  is  probably 
SlOo,  or  some  sihcate,  and  must  be  fluxed  with  NajCOg  and  K3CO3 


302 


QUALITATIVE     ANALYSIS. 


TABLE    I.— SCHEME    FOR 


Add  HCl  to  Solution. 


PREC. 

i'LLTRATE 

Ag  Pb  Hg 
BoilinH.O 

Sol.      Prec. 

Add  H,S. 

PRECIPITATE. 

Hg  Pb  Bi  Cd  Cu  As  Sb  Sn  Au  Pt. 

p,  1  Ag  Hg 
P^  NH.OH 

Digest  with  yellow  (NHJ^S. 

^ 
? 

,SW.  iVec.l 

Eesidue.                                                 Solution. 

Ag 

Hg 

Hg  Pb  Bi  Cd  Cu              }               As  Sb  Sn  Au  Pt 

w 

i 
? 

2 

vr 

Boil  in  HNO3.                 InHapparatiis  withZn  cfcH,SO. 

b 
o 

^6S. 

Sol. 

Ocw.                    Besidue.            \ 

.       ^x-                                                                         1 

w 

Hg. 

Pb  Bi  Cd  Cu 

AsSb 

Sn  Au  Pt 

2- 

Izj 

With  H,SO.. 

Pass  into 

Boil  in  HCl. 

o' 

p 

U 

AgNOa 

i^ 

i- 

'< 

Prec. 

Sol. 

Sol.      Ret. 

Sol.            Res. 

p" 

CD 

Pb 

Bi  Cd  Cu 

As 

Sb 

Sn 

AuPt 

1 

1 

NH.OH. 
Prec.             Sol. 

and 
Ag 

ID 

HCl  and 
HNOj. 

3 

p" 

cl- 

-&;. 

0 



Bi 

Cd  Cu 

TO 
8= 

KCy  and 
H2S 

1 

Au 

Pt 

P 
0 

1 

Prec.      Sol. 

^ 

9 

w 

0 

p. 

.*' 

CO 

0 

rt- 

t: 

•* 

s 

Cd. 

Cu 

Ki 

s- 

hj 

£i 

^. 

:^ 

w 

o* 

? 

0 
0 

g 

'9 

.:^ 

DD 

^ 

P 

+ 

o 

n> 

0 

«-- 

pi 

0 

p 

UALITATIVE     ANALYSIS. 


303 


COMPLETE    ANALYSIS. 


FILTRATE. 


Add  H,S. 

FILTRATE. 


Add  NH.OH  and  (NHJ^S. 


Free. 

Filtrate. 

Co  Ni  Fe  Cr  Mn  Al  Zn 

Add  (NHO^COa. 

■ 

Dilute  HCl. 

Sol. 

Prec. 

FUtrate. 

Res. 

Ba  Sr  Ca 
Dissolve  in 

Fe  Cr  Mn  Al  Zn 

CoNi. 

Boil  in  NaOH. 

Acetic  Acid ; 

Mg  K  Na 

^ 

2  Parts. 

2  Parts. 

§■ 

Prec.                          Sol. 

/.                     //. 

I.                       11. 

^ 

Fe  Cr  Mn 

Al 

Zn 

t? 

Fuse  with  KNO3 

0 
P^ 

Add 

Ca 

Mg 

O 

and  NaoCOa.  Dis- 
solve in  HoO. 

K^Ci-O, 
Prec.    Sol. 

< 
p 

^fe<.             Sb;. 

p 
B 

0 

+ 

P  1 

Ba 

Sr 

S 

Fe 

Cr 

Mn 

P' 

H 

t> 

CD 

!zi 

s^  £ 

P 
CO 

« 

CO 

0 

CD 

Pi 

0 

0 

3 
0 

Pi 
Pi 

.i 

b 

05 

P 
p 

3 
Q 

0 

+ 

s 

p 

Pi 
Pi 

!zi 

•d 

+ 

CD 

0  » 

■  1 

a- 

» 

•d 

.■^ 

Q 

^ 

^ 

w 

0 

P- 

-^ 

1 

5' 

09 

Test  for  NH.  in 
the  original  so- 

0 

a 

It! 

0 

lution,  by  heat- 

!» 

-  0 

B 

P 

i  n  g         with 

« 

W 

^ 

1     ^ 

NaOH,  NH3  is 

CD 

1 

given  off. 

QUESTIONS  FOR  CLASS  USE. 


I.  — INTRODUCTION. 

Page  1,  2. — Define  chemist^J^  What  is  the  distinction  between 
physical  and  chemical  phenomena?  Illustrate.  Can  matter  be 
destroyed  ?  "What  becomes  of  it  when  it  disappears  ?  What 
properties  do  gases  possess  which  prove  them  to  be  matter  ?  "UTiat 
is  an  element  ?  How  many  are  known  ?  Is  it  probable  that  all 
the  elements  have  been  discovered  ?  What  is  a  compound  ?  Are 
compounds  like  their  elements?  Illustrate.  Define  chemical 
affinity.     Illustrate.     How  does  it  act? 

3,  4.— What  is  the  action  of  heat?  Of  light?  Of  electricity? 
Of  solution?  Illustrate.  State  the  laws  of  definite  and  multiple 
proportions.  What  is  the  constitution  of  bodies?  What  is  a 
molecule?  An  atom?  How  do  atoms  difi'er?  What  is  atomic 
weight  ?    Molecular  weight  ?    Valence  ? 

5-7. — What  notation  is  used  in  chemistry?  Illustrate.  What 
is  the  formula  of  a  substance?  Illustrate.  How  are  reactions 
represented?  Illustrate.  How  are  elements  named?  Com- 
pounds? How  are  elements  classified?  What  is  the  distinction 
between  Inorganic  and  Organic  Chemistry? 

II.  —  INORGANIC     CHEMISTRY. 
1.  — THE     NON-METALS. 

11.  Oxygen. — Give  the  symbol  and  atomic  weight  of  oxygen. 
What  is  the  meaning  ?  Where  is  0  found  ?  How  may  it  be  pre- 
pared ? 

12. — How  is  0  prepared  from  potassium  chlorate  and  manga- 
nese dioxide?  Give  the  reaction.  What  becomes  of  the  potas- 
sium chloride  which  is  formed  ? 

13-16. — What  is  the  use  of  the  black  oxide  of  manganese? 
Name   the    properties   of   0.    What   is   oxidation?     An   oxide? 


QUESTIONS     FOR     CLASS     USE,  305 

Show  that  0  is  a  supporter  of  combustion.  What  compounds 
are  formed  in  these  illustrations?  Describe  the  action  of  the  0 
in  the  air.  Describe  the  action  of  0  on  fuel.  On  impure  water. 
On  writing-ink.  On  red-hot  iron.  On  damp  knives  and  forks. 
By  what  means  is  the  0  carried  through  the  system? 

17,  18. — What  work  does  0  perform  in  the  body?  Why  is 
the  blood  in  the  arteries  red  and  in  the  veins  blue?  What 
chemical  processes  are  included  by  the  chemist  under  the  term 
oxidation?  Does  fire  differ  essentially  from  decay?  Is  heat 
always  produced  by  oxidation  ?  Illustrate.  What  is  the  igniting 
point  ?  How  are  fires  extinguished  ?  What  causes  spontaneous 
combustion  ? 

19,  20. — What  is  the  chemical  process  of  starvation?  Why 
d  es  unusual  exercise  cause  one  to  breathe  more  rapidly?  "Why 
does  running  cause  panting?  "^Tiy  do  we  need  extra  clothing 
when  we  sleep,  even  at  midday,  in  the  summer  ?  How  do  hiber- 
nating animals  illustrate  this  ?  How  does  a  cold-blooded  animal 
differ  from  a  warm-blooded  one  ?  How  does  0  give  us  strength  ? 
What  is  potential  energy?    Kinetic  energy? 

21,  22. — Show  how  0  is  constantly  burning  the  body.  Is 
there  any  part  of  the  body  that  is  permanent?  Illustrate  the 
rapidity  of  this  change.  Show  the  truth  of  the  paradox — "We 
live  only  as  we  die."  Why  do  we  need  food  and  sleep?  Show 
how  0  acts  as  a  scavenger  in  nature.  In  what  sense  is  0  the 
sweeper  of  the  body  ?  Is  this  a  useful  provision  ?  How  much  0 
does  each  adult  need  per  day?    Total  amount  used  daily? 

23,  24. — What  would  be  the  result  if  the  air  were  pure  0? 
What  objects  would  escape  combustion?  What  is  ozone?  Where 
is  it  noticed  ?  Preparation  ?  Test  ?  Properties  ?  Is  it  a  valuable 
constituent  of  the  air?  How  does  the  ozone  molecule  differ 
from  that  of  0  ? 

25,  26. — What  are  the  laws  for  the  effects  of  change  of  tem- 
perature and  pressure  on  gases?  How  can  the  weight  of  any 
volume  of  gas  be  calculated  ?  How  can  the  weight  of  a  gas 
produced  by  a  given  weight  of  re-agents  be  found  ? 

27,  28.  Nitrogen. — Symbol  and  atomic  weight?  Why  so 
called?  Sources?  Occurrence?  Preparation?  Properties?  Why 
does  a  person  drown  in  water  ?  Would  a  person  die  in  pure  N  ? 
What  is  the  peculiarity  of  the  nitrogen  compounds? 


306  QUESTIONS     FOR     CLASS     USE. 

29,  30. — What  causes  flesh  to  decompose  so  much  more 
easily  than  wood?  Does  the  N  we  take  in  at  each  breath  do 
us  any  direct  good  or  harm?  Where  do  we  get  N  to  make  our 
flesh?  Describe  the  action  of  N  and  0  in  our  stoves.  T\Tiere 
do  plants  obtain  N  ?  State  the  main  distinction  between  0  and 
N.  What  is  the  oflSce  of  the  N  in  the  air?  Show  that  the  pro- 
portion of  0  and  N  in  the  atmosphere  gives  us  the  golden 
mean. 

31,  32. — Formula  ana  molecular  weight  of  nitric  acid?  Ex- 
plain its  occasional  presence  in  the  atmosphere.  Preparation? 
Properties?  What  color  does  it  give  to  wood?  Uses?  Illus- 
trate its  oxidizing  action.  What  is  aqua  regia?  Describe  the 
process  of  etching.  The  action  of  HNO3  on  Sn.  What  are  the 
red  fumes  which  pass  off? 

33,  34. — Formula  and  molecular  weight  of  nitrous  oxide? 
The  common  name?  Preparation?  Reaction?  Properties? 
What  is  the  effect  of  nitrous  oxide  on  the  human  system? 
State  its  use  in  surgical  operations.  Formula  and  molecular 
weight  of  nitric  oxide?  Its  preparation?  Why  is  the  gas  in 
the  flask  colored  ?  What  compound  is  formed  with  0  ?  Prop- 
erties of  NO?    What  are  the  fumes  which  it  forms  in  the  air? 

35-37. — Formula  and  molecular  weight  of  ammonia?  Why 
so  called?  Its  old  name?  What  is  aqua  ammonia?  Whence 
obtained  ?  Give  the  reaction.  Properties  ?  How  liquefied  ?  De- 
fine the  nascent  state. 

38,  39.  Hydrogen. — Symbol  and  atomic  weight?  Meaning 
of  the  name?  Occurrence?  Preparation?  Reaction?  What 
compound  is  formed  ?  Properties  ?  Is  H  a  metal  ?  A.ns. — In 
all  reactions  it  plays  the  part  of  a  metal,  and,  like  most  of  the 
metals,  is  electro-positive.  Its  levity?  Will  it  destroy  life? 
Effect  on  the  voice  ?    Use  in  filling  balloons  ? 

40-44. — What  is  the  product  of  the  combustion  of  H  ?  What 
becomes  of  it  ?  Will  the  gases  H  and  0  combine,  if  mixed  ?  De- 
scribe the  hydrogen  gun.  Cause  of  the  report?  \Vhat  is  the 
action  of  platinum  sponge  on  a  jet  of  H  ?  Describe  Dobereiner's 
lamp.     Explain  the  heat  produced  by  burning  H. 

How  are  hydrogen  tones  produced?     Explain. 

45-47.  Watek. — Formula  and  molecular  weight  of  water? 
How  may  its  composition    be   proved  ?     What    is    the    freezing 


QUESTIONS     FOR     CLASS     USE.  307 

and  the  boiling  point  of  water?  What  injury  may  a  small 
quantity  of  HoO  do,  if  thrown  on  a  fire?  Explain.  Can  HoO, 
then,  be  burned?  Illustrate  the  abundance  of  HoO  in  the 
animal  world.  Vegetable  world.  Mineral  world.  Why  will 
blue  vitriol  lose  its  color  if  heated?  What  is  "burnt  alum"? 
Water  of  crystallization? 

48-52. — Show  the  adaptation  of  H,0  as  a  solvent.  What 
water  is  the  purest  ?  Why  does  rain-water  taste  so  insipid  ? 
Is  river-water  a  healthy  drink?  What  is  hard  water?  Soft 
water?  Why  does  the  hardness  of  water  varj^  in  different 
places?  Is  hard  water  healthful?  How  may  we  detect  organic 
matter  in  HoO?  What  minerals  are  most  common  in  water? 
What  is  the  "fur"  in  a  tea-kettle?  Why  does  soap  curdle  in 
hard  water?  How  could  Salt  Lake  be  freshened?  What  is  the 
use  of  the  air  in  H^O?  How  do  fish  breathe?  Does  the  air 
in  water  differ  from  ordinary  air?  How?  Why  is  boiled 
water  so  insipid  ?  Give  some  of  the  paradoxes  of  water.  Name 
the  various  uses  of  water.     ("Physics,"  p.  201.) 

53-55.  Caebon. — Symbol  and  atomic  weight?  Illustrate  the 
abundance  of  C.  Is  it  more  characteristic  of  the  vegetable  than 
of  the  mineral  kingdom?  What  are  its  forms?  Proof  of  these 
allotropic  states  ?  What  is  an  allotropic  condition  ?  What  is  the 
diamond?  Properties?  Has  it  ever  been  made  artificially? 
What  is  a  carat?  How  is  the  diamond  ground?  Describe  the 
three  modes  of  cutting.  What  gives  the  diamond  its  value? 
Common  name  for  graphite?    Origin?    Uses  of  graphite? 

56,  57. — Describe  the  process  of  making  a  lead-pencil.  What 
is  a  black-lead  crucible?  What  is  British  Luster?  Lamp-black? 
Uses?  Fitness  for  printing?  What  can  you  say  about  ancient 
MSS.  ?  What  is  soot  ?  What  causes  the  burning  of  chimneys  ? 
Does  this  occur  oftener  when  wood  than  when  coal  is  used  as  a 
fuel?  How  is  charcoal  made?  What  is  coke?  Uses?  Gas- 
carbon  ? 

58,62. — Bone-black?  Uses?  How  is  sugar  refined ?  Describe 
the  formation  of  coal.  Difference  between  bituminous  and 
anthracite  coal?  Why  is  coal  found  in  layers,  with  slate,  etc., 
between  ?  "V^at  proof  have  we  that  coal  is  of  vegetable  origin  ? 
Describe  the  formation  of  peat.  Uses?  What  is  muck?  Use? 
Name  some  of  the  diverse  properties  and  uses  of  C. 


808  QUESTIONS     FOR     CLASS     USE. 

63.  Carbon  Dioxide.  —  Formula  and  molecular  weight? 
Occurrence?  How  is  it  constantly  formed?  Preparation?  Re- 
action ? 

64,65. — Test?  What  causes  the  pellicle  on  lime-water ?  What 
does  this  show?  Prove  that  we  exhale  CO,.  Give  the  proper- 
ties of  CO,.  Prove  that  CO^  is  heavier  than  air.  A  non-sup- 
porter of  combustion.     That  it  contains  C. 

66,  67. — What  test  should  be  employed  before  descending 
into  a  deep  well  or  an  old  cellar  ?  How  can  you  remove  the  foul 
air?  Tell  about  the  Grotto  del  Cane.  Is  COg  directly  poisonous? 
What  is  choke-damp?    Fire-damp?    Which  is  more  dreaded? 

68,  69. — Has  CO,  been  used  in  extinguishing  fires?  Tell 
about  the  absorption  of  CO,  by  H,0,  What  is  soda-water? 
How  is  CO,  liquefied?  Why  does  the  liquid  solidify  Avhen  ex- 
posed to  the  air?  What  principle  in  natural  philosophy  does 
this  illustrate?  How  low  a  degree  of  cold  has  been  produced  in 
this  manner?  Describe  the  need  of  ventilation.  How  is  the  air 
expired  from  our  lungs  made  useful  ?  Is  a  single  opening 
sufficient  to  ventilate  a  room?  What  practical  application  do 
you  make  of  this  subject? 

70,  71. — Formula  and  molecular  weight  of  carbon  monoxide? 
Properties?  Where  is  it  often  formed?  Explain.  Practical  im- 
portance of  this  fact?  What  causes  the  unpleasant  odor  of  coal- 
gas  ?  Formula  and  molecular  weight  of  light  carburetted 
hydrogen?     Properties?     How  is  it  formed? 

72,  73. — Name  places  where  it  is  found  in  great  quantities. 
Formula  and  molecular  weight  of  heavy  carburetted  hydrogen? 
Properties  ?  How  made  ?  What  gases  mainly  compose  coal-gas  ? 
Which  is  the  most  valuable  ?  Describe  the  manufacture.  Is  the 
odor  an  advantage?  Is  coal-gas  explosive?  Why  is  the  jet  flat? 
When  we  turn  the  gas  very  low,  or  the  supply  is  insufficient, 
why  is  the  flame  blue? 

74,  75. — What  is  water-gas?  Formula  and  molecular  weight 
of  cyanogen?  Meaning  of  the  name?  Preparation?  What  are 
its  compounds  called?  What  is  the  yellow  prussiate  of  potash? 
The  red?  Ans. — The  ferricyanide,  KaFeCy^.  Properties  of  Cy? 
What  is  a  compound  radical?  Formula  of  hydrocyanic  acid? 
Common  name?  Where  found?  Antidote?  What  are  the  ful- 
minates?   How  are  gun-caps  made? 


QUESTIONS     FOR     CLASS     USE.  309 

76,  77.  Combustion. — Define.  What  is  a  combustible  ?  A  sup- 
porter of  combustion?  (The  difference  between  these  two  is 
nicely  shown  in  the  experiment  with  H  on  p.  40.)  A  burnt  body? 
Ans. — A  body  which  has  combined  with  0. — Example:  a  stone, 
water.  Upon  what  does  the  amount  of  heat  produced  by  com- 
bustion depend  ?  The  intensity  ?  Why  do  we  need  a  draught  to 
a  stove?  Does  combustion,  in  its  chemical,  sense,  commence 
before  the  fuel  catches  fire?  Why  do  we  use  "kindlings"  in 
starting  a  fire?  Why  can  we  light  pitch-pine  so  easily?  What 
are  hydrocarbons?  What  are  the  ordinary  products  of  combus- 
tion? What  causes  the  dripping  of  stove-pipes?  What  are  the 
ashes?  Why  does  fresh  fuel  produce  a  flame?  Show  how  ad- 
mirably C  is  adapted  for  a  fuel.  "What  would  be  the  effect  if 
COg  were  not  a  gas?  Define  flame.  Describe  the  burning  of  a 
candle.     Show  that  flame  is  hollow. 

78,  79.— What  causes  the  hght?  Wliy  is  the  flame  blue  at 
the  bottom?  Products  of  combustion?  Tests?  Why  does  the 
wick  turn  black  ?  What  causes  the  coal  at  the  end  of  the  wick  ? 
Why  does  snuffing  brighten  the  light  ?  Why  does  a  draft  of  air,  or 
a  sudden  movement  of  the  candle,  cause  it  to  smoke?  Why  is 
the  flame  of  a  candle  or  lamp  red,  or  yellow?  Ans. — Because 
the  heat  is  not  sufficient  to  cause  the  carbon  to  emit  all  the  rays 
of  the  spectrum.  Use  of  plaited  wicks  ?  Object  of  a  chimney  to 
a  lamp  ?  A  flat  wick  ?  Advantage  of  an  Argand  lamp  ?  T^Tiat  is 
the  film  which  gathers  on  the  chimney  when  the  lamp  is  first 
lighted  ?  Why  does  this  soon  disappear  ?  Why  do  tar,  spirits  of 
turpentine,  etc.,  burn  with  much  smoke? 

80-82. — Why  does  alcohol  give  much  heat  and  no  smoke? 
Describe  Davy's  safety-lamp.  Illustrate  this  by  a  wire  gauze 
over  the  flame  of  a  candle.  Describe  Bunsen's  burner.  Why 
does  it  give  great  heat,  little  hght,  and  no  smoke  ?  Describe  the 
oxy-hydrogen  blow-pipe.  Why  does  it  give  great  heat  and  little 
hght?    What  is  the  calcium  light? 

83. — Describe  the  mouth  blow-pipe.  The  blow-pipe  flame. 
Where  is  the  hottest  point  in  the  flame?  What  is  the  reducing 
flame?  The  oxidizing  flame?  Why  does  blowing  on  a  candle- 
flame  extinguish  it? 

85-89.  The  Atmosphere. — Name  the  constituents.  Propor- 
tion.    State  the  comparison.     What  is  diffusion?    What  effect 


310  QUESTIONS     FOR     CLASS     USE. 

does  this  have  on  the  air?  Is  the  air  a  chemical  compound? 
Illustrate.  Has  each  constituent  a  special  use?  Name  the  uses 
of  0.  Of  CO  2.  Explain  the  chemical  change  which  takes  place 
in  the  leaf.  What  is  the  influence  of  house-plants  upon  the 
atmosphere  of  a  room  ?  What  can  you  say  of  the  exact  balance 
kept  between  the  wants  of  animals  and  plants? 

90,  91. — What  relation  exists  between  animals  and  plants? 
Which  gathers  and  which  spends  the  solar  energy?  Which  per- 
forms the  office  of  reduction?  Which  that  of  oxidation?  How 
is  the  solar  energy  set  free?  What  is  the  use  of  the  waterj' 
vapor  in  the  air?  Which  of  the  constituents  are  permanent? 
Is  this  a  wise  pro\'ision  ?  What  effect  does  this  permanence 
have  upon  sound  ?  Why  ought  the  vapor  to  be  easily  changed 
to  the  liquid  form? 

92.  The  Halogens.  —  Name  them.  Symbols  and  atomic 
weights?  Compare  the  halogens  with  each  other.  TVTiat  com- 
pounds do  they  form  ?  Why  is  chlorine  so  called  ?  Occurrence  ? 
Preparation  ?    Reaction  ? 

93-95. — Properties  of  CI?  What  action  does  CI  have  on  phos- 
phorus, arsenic,  etc.  ?  Why  does  a  solution  of  the  gas  soon 
become  acid?  What  is  its  action  on  organic  bodies?  Why  does 
CI  act  more  readily  in  the  presence  of  moisture?  Its  action  on 
turpentine?  On  printers'  ink?  Describe  the  chemical  change 
in  domestic  bleaching.  The  method  of  bleaching  on  a  large  scale. 
What  is  the  advantage  of  using  CI  over  other  disinfectants? 

96,  97. — How  may  the  gas  be  set  free?  How  are  hospitals 
purified  ?  "\Yliat  mixture  would  liberate  CI  in  the  greatest  quan- 
tities? Formula  and  molecular  weight  of  hydrochloric  acid? 
Common  name?  Preparation?  Reaction?  Properties?  What 
are  its  compounds  termed?    Tests?    What  is  aqua  regia? 

98-100. — What  is  an  acid  ?  A  base  ?  A  salt  ?  How  are  acids 
and  salts  named?  Illustrate.  Tell  what  you  can  about  bro- 
mine.   Its  uses. 

101,  102. — Why  is  iodine  so  called?  Its  source?  Properties? 
Test  ?  What  is  the  pecuharity  of  fluorine  ?  Occurrence  ?  What 
acid  does  it  form?  For  what  is  this  acid  noted?  Describe  the 
process  of  etching  with  HF.  Why  is  not  HF  kept  in  ordinary 
bottles?    Is  it  dangerous  to  use? 

103.   Sulphur. — Symbol  and  atomic  weight ?    Sources?   What 


QUESTIONS     FOR     CLASS     USE.  311 

is  the  principle  of  hair-dyes  ?  Why  do  eggs  tarnish  silver  spoons  ? 
"What  is  the  difference  between  brimstone  and  flowers  of  sul- 
phur ?  Properties  ?  Solvent  ?  Allotropic  forms  ?  Describe  the 
changes  produced  by  heating. 

104,  105. — Uses  of  S?  Formula  and  molecular  weight  of 
sulphur  dioxide?  Where  is  it  familiar?  What  is  sulphurous 
acid?  What  salts  does  it  form?  Uses  of  SO,  in  bleaching? 
Why  are  new  flannels  liable  to  turn  yellow  when  washed? 
Formula  and  molecular  weight  of  sulphuric  anhydride?  By 
what  other  name  is  it  known  ?  Preparation  ?  Properties  ?  Why 
is  Nordhausen  acid  so  called? 

106,  107. — Formula  and  molecular  weight  of  sulphuric  acid? 
Common  name  ?  State  its  importance.  "VYhat  are  its  compounds 
called?  Illustrate  the  making  of  HjSO^.  Describe  its  manu- 
facture.    Reaction  ? 

108-110. — Properties?  What  especial  property?  Illustrate. 
Its  strength  ?  Color  of  its  stain  on  cloth  ?  How  removed  ?  On 
wood  ?  Cause  of  this  action  ?  Test  ?  Formula  and  molecular 
weight  of  hydrogen  sulphide  ?  Where  is  it  found  ?  Preparation  ? 
Reaction  ?  Properties  ?  Use  ?  Color  of  the  precipitates  ?  Test  ? 
Formula  and  molecular  weight  of  carbon  sulphide?  Prepara- 
tion? Properties?  Uses?  How  does  it  illustrate  the  force  of 
chemical  affinity? 

Ill,  112.  Valence. — What  is  valence?  Illustrate.  What 
names  distinguish  the  different  valence  of  atoms?  What  are 
monobasic,  bibasic,  tribasic  acids?  What  is  a  normal  salt?  An 
acid  salt? 

113.  Phosphorus.  —  Symbol  and  atomic  weight?  Why  so 
called  ?  Occurrence  ?  In  what  parts  of  the  body,  and  in  what 
forms,  is  it  found? 

114-116. — Preparation?  Properties?  Caution  to  be  observed? 
Is  phosphorus  poisonous?  What  is  the  product  of  its  com- 
bustion? Describe  the  amorphous  form  of  phosphorus.  What 
is  the  principal  use  of  phosphorus?  Describe  the  making  of 
the  lucifer  match.  The  safety  match.  What  compounds  are 
formed  in  the  burning  of  a  match?  What  is  phosphorescence? 
Its  cause  ? 

117. — Formula  and  molecular  weight  of  hydrogen  phosphide? 
Preparation  ?    Properties  ? 


312  QUESTIONS     FOR     CLASS     USE. 

117-120.  Arsenic. — Symbol  and  atomic  weight?  Common 
name?  Test?  What  is  commonly  sold  as  arsenic  or  ratsbane? 
Preparation  of  arsenic  trioxide?  Properties?  What  can  you  tell 
of  its  antiseptic  property?  Antidotes?  Describe  Marsh's  test. 
How  can  the  As  be  distinguished  from  Sb?  What  is  said  of 
arsenic  eating? 

120-122.  Boron. — Symbol  and  atomic  weight?  Source? 
Describe  the  scene  in  Tuscany  where  it  is  found.  Process  of 
obtaining  boric  acid?  Formula  and  molecular  weight  of  borax? 
Uses? 

123-126.  Silicon. — Symbol  and  atomic  weight?  Occurrence? 
Common  names  of  SiOj  ?  What  gems  does  it  form?  What 
is  sand?  Properties?  Why  is  it  called  an  anhydride?  Is  silica 
soluble  in  HoO?  How  does  it  get  into  plants?  In  what  plants 
is  it  found?  Explain  the  process  of  petrifaction.  What  is  said 
of  the  antiquity  of  glass  ?  Pliny's  story  of  its  origin  ?  What  is 
said  of  its  value  in  the  twelfth  century?  Name  the  four  va- 
rieties of  glass  and  the  composition  of  each.  What  are  the 
essential  ingredients  of  glass?  How  is  glass  colored?  Name 
the  oxides  used.  Why  is  flint-glass  so  called  ?  How  is  glass 
annealed  ?  Describe  the  Prince  Rupert's  drop.  How  are  Vene- 
tian balls  made  ?     Tubes  ?     Beads  ? 

2  .-T  HE      M  ETA  LS. 

127.  Potassium. — Symbol  and  atomic  weight?  History  of 
its  discovery  ?    Source  ? 

128,  129. — How  do  we  get  our  supply?  Preparation?  Prop- 
erties? How  must  it  be  kept?  Reaction  when  thrown  on  HjO? 
Formula  and  molecular  weight  of  caustic  potash?  Properties? 
Its  feel?  Its  affinity  for  HoO?  Uses?  Formula  and  molecular 
weight  of  potassium  carbonate?  Common  name?  Preparation? 
What  part  of  the  tree  furnishes  the  most  potash?  What  is  the 
derivation  of  the  word  ?  Formula  and  molecular  weight  of 
acid  potassium  carbonate  ?  Common  names  ?  Preparation  ? 
Formula  and  molecular  weight  of  potassium  nitrate?  Com- 
mon names  ?     'WTiere  is  it  found  ? 

130,  131. — How  is  it  prepared  artificially  ?  How  much  water 
would  be  required  to  dissolve  a  pound  of  this  salt  ?    Properties  ? 


QUESTIONS     FOR     CLASS     USE.  313 

Uses?  What  is  the  composition  of  gunpowder?  Cause  of  its 
explosive  force?  Uses  of  potassium  chlorate?  Potassium  bi- 
chromate ?    Composition  of  fire-works  ? 

Sodium. — Symbol  and  atomic  weight?  Source?  What  pro- 
portion does  it  form  of  common  salt  ? 

132,  133. — What  element  does  it  resemble?  Reaction  when 
thrown  on  water  ?  What  compound  is  formed  ?  Test  ?  Formula 
and  molecular  weight  of  common  salt?  What  use  does  it  sub- 
serve in  the  body?  Is  salt  abundant?  Describe  the  manu- 
facture. "What  is  solar  salt?  Describe  the '"  hopper-shape " 
crystal.  Is  it  best  to  heat  the  water  for  dissolving  salt?  What 
is  a  saturated  solution? 

134,  135. — Formula  and  molecular  weight  of  sodium  hydrox- 
ide? Common  name?  Uses?  Formula  and  molecular  weight  of 
sodium  sulphate  ?  Common  name  ?  Preparation  ?  Reaction  ? 
What  curious  property  has  this  salt  ?  Why  will  the  dropping 
in  of  a  crystal  cause  solidification?  Formula  and  molecular 
weight  of  sodium  carbonate?  Common  names?  Why  called 
carbonate  of  soda?  Describe  its  manufacture.  Why  will  Na^COj 
soften  hard  water?  Formula  and  molecular  weight  of  acid 
sodium  carbonate?  Common  name?  Why  called  bicarbonate 
of  soda?     Preparation?     Use? 

136,  137. — Give  the  theory  of  ammonium.  How  is  the  for- 
mula NH4OH  obtained?  What  is  a  compound  radical?  Formula 
and  molecular  weight  of  ammonium  chloride?  Preparation? 
Uses  ?  Formula  and  molecular  weight  of  ammonium  carbonate  ? 
Common  names?  Uses?  Formula  and  molecular  weight  of 
ammonium  nitrate?    Preparation?    Uses? 

138,  139.  Calcium. — Symbol  and  atomic  weight  ?  Source  ?  In 
what  part  of  the  body  is  it  found?  In  what  form  do  we  com- 
monly see  it?  Formula  and  molecular  weight  of  lime?  Prepa- 
ration? Describe  a  lime-kiln.  Properties  of  CaO  ?  Test?  What 
is  the  difference  between  "water-slaked"  and  "air-slaked  "  lime? 
Uses?  What  is  whitewash?  Concrete?  Hard-finish?  Calcimin- 
ing?  Theoiy  of  the  hardening  of  mortar?  Why  are  newly-plas- 
tered walls  so  damp?  Will  mortar  harden  if  protected  from  the  air? 

140,  141. — Action  of  lime  on  the  soil?  Will  it  not  lose  its 
beneficial  effect  after  a  time  ?  Should  it  be  applied  to  a  compost 
heap?    How  can  this  waste  be   avoided?    How  would  you  test 


314  QUESTIONS     FOR     CLASS     USE. 

for  the  escaping  N  H  3  ?  Action  of  lime  on  copperas  ?  How  does 
the  copperas  get  in  the  soil?  Uses  of  lime?  Formula  and 
molecular  weight  of  carbonate  of  Lime?  Occurrence?  How  are 
stalactites  and  stalagmites  formed?  What  is  petrified  moss? 
Whiting?  Marble?  Chalk?  Marl?  Formula  and  molecular 
weight  of  calcium  sulphate?  Common  names?  What  is  plaster 
of  Paris?  Why  does  plaster  of  Paris  harden,  if  moistened? 
Ans. — Because  it  absorbs  water  again. 

142,  143. — Uses?  What  is  plaster?  How  prepared  for  use  as 
a  fertilizer?  Ans. — It  is  ground  into  a  fine  powder.  Tell  the 
story  of  Franklin.  What  is  the  difference  between  sulphate 
and  sulphite  of  lime?  Formula  and  molecular  weight  of  phos- 
phate of  lime  ?  What  is  the  superphosphate  ?  Use  ?  Uses  of 
the  salts  of  barium  and  strontium?  "VNHiat  is  heaA^'  spar? 
Bary  tes  ? 

144.  Magnesium. — Symbol  and  atomic  weight?  Occurrence? 
How  can  you  tell  if  a  stone  contains  Mg?  Ans. — It  generally 
has  a  soapy  feel.  Properties?  For  what  is  it  noted?  Product 
of  its  combustion?  Formula  and  molecular  weight  of  magne- 
sium sulphate?    Common  name?    What  is  magnesia  alba? 

145.  Aluminium. — Sjinbol  and  atomic  weight?  Occurrence? 
Properties?  Solvents?  What  can  you  say  of  its  abundance  and 
probable  usefulness?  What  is  alumina?  What  crystals  and 
gems  does  it  form? 

146.  147. — What  is  emery?  What  is  common  clay?  Use  in 
the  soil  ?  In  the  arts  ?  What  is  ochre  ?  Fuller's  earth  ?  Explain 
the  process  of  glazing  pottery  ware.  What  is  the  salt  glaze? 
The  litharge  glaze?  What  objection  to  the  latter?  What  gives 
color  to  brick  ?  What  is  the  peculiarity  of  white  brick  ?  How  is 
alum  made?  Name  different  kinds  of  alum.  Which  kind  is  the 
common  commercial  alum?  Use  of  alum  in  dyeing?  How  are 
alum  crystals  made?  Ans. — They  are  obtained  by  suspending 
threads  in  a  saturated  solution  of  this  salt.  In  this  manner 
alum  baskets,  bouquets,  etc.,  are  formed  of  any  desired  color. 

148. — What  is  spectrum  analysis?  Is  it  a  reliable  test ?  Illus- 
trate its  delicacy.     What  is  the  spectroscope? 

150.  Iron. — Symbol  and  atomic  weight?  Tell  what  you  can 
of  its  value  to  the  world.  How  is  its  use  a  symbol  of  a  nation's 
progress  ? 


QUESTIONS     FOR     CLASS     USE.  315 

151,  152. — State  how  its  value  is  enhanced  by  labor.  Name 
the  sources  of  iron.  Common  ores.  Describe  the  process  of 
smelting  iron  ore.  Why  is  hot  air  used  for  the  blast  ?  Reaction 
of  the  Ume?    What  becomes  of  the  0  in  the  ore? 

153. — Origin  of  the  term  "pig-iron"?  Name  the  varieties  of 
iron.  Difference  between  them.  What  is  cast-iron?  Its  proper- 
ties ?  Uses  ?  How  is  iron  adapted  for  castings  ?  What  is  chilled 
iron?    Wrought  iron? 

154. — Preparation?  Effect  of  jarring?  Illustrate  its  mallea- 
bility. What  is  steel?  Preparation?  In  making  steel  tools, 
how  does  the  workman  judge  of  the  temper?  How  are  cheap 
knives  made? 

155. — Describe  Bessemers  process.  Cause  of  the  changing 
colors  often  seen  in  the  scum  over  standing  water? 

156,  157.  —  Name  the  different  oxides  of  iron.  Give  the 
formula  of  each.  What  peculiar  property  is  possessed  by  the 
ferric  oxide  and  ferric  hydroxide?  What  is  iron  carbonate?  By 
what  name  is  it  known?  Cause  of  the  ferruginous  deposit 
around  chalybeate  springs?  Formula  and  molecular  weight  of 
iron  disulphide  ?    Common  names  ?    What  is  chameleon  mineral  ? 

158,  159. — Uses  of  iron  disulphide?  Formula  and  molecular 
weight  of  ferrous  sulphate?    Common  names?    Uses? 

Zinc. — Sjonbol  and  atomic  weight?  Source?  Preparation? 
Reaction?  Is  it  malleable?  Will  it  oxidize  in  the  air?  Uses? 
What  is  philosopher's  wool?  What  is  galvanized  iron?  Are 
water-pipes  made  of  this  material  safe  ?  Formula  and  molecular 
weight  of  zinc  oxide?  Use?  Formula  and  molecular  weight  of 
zinc  sulphate  ?    Use  ? 

160.  Tin.  —  Symbol  and  atomic  weight?  Where  found? 
Properties?  What  is  the  "tin  cry"?  What  is  common  tin- 
ware? Action  of  HNO3  onSn?  What  can  you  say  of  the  manu- 
facture of  pins? 

161.  Copper.  —  Sjonbol  and  atomic  weight?  Where  found? 
Antiquity  of  the  mines  ?  What  is  malachite  ?  Properties  of  C  u  ? 
Color  of  its  vapor?    Solvent?    Test?    ^Vhat  is  verdigris? 

162.  163.— Black  oxide  of  copper?  What  is  the  danger  of 
using  a  copper  kettle?  Formula  and  molecular  weight  of  cop- 
per sulphate?    Common  name?    Uses? 

Lead.— Symbol  and  atomic  weight?     Source?     Preparation? 


316  QUESTIONS     FOR     CLASS     USE. 

Properties?  Its  effect  on  the  human  system?  Action  of  water 
on  lead?  Is  there  more  danger  with  hard,  or  with  soft  water? 
What  precaution  should  always  be  used  with  lead  pipes  ?  What 
is  the  test  of  lead?    What  is  "litharge"? 

164. — Its  uses?  "Red-lead"?  Its  uses?  What  is  "white- 
lead"?  Describe  its  manufacture.  With  what  is  it  adulterated? 
What  is  "sugar  of  lead"?  Properties?  Antidote?  Explain  the 
formation  of  the  lead-tree. 

165,  166.  Gold. — Symbol  and  atomic  weight?  Source? 
Preparation?  What  is  an  amalgam?  Quartation?  Properties? 
Solvent?    Process  of  making  gold-leaf? 

167-172.  Silver.  —  Symbol  and  atomic  weight?  Source? 
Preparation,  1,  from  the  sulphide;  2,  horn-silver;  3,  lead? 
Describe  the  process  of  reduction  at  the  West.  What  is  cupel- 
lation?  Properties  of  silver?  Solvent?  Test?  What  is  the 
common  name  of  nitrate  of  silver?  What  is  its  action  on  the 
flesh?  How  may  its  stain  be  removed?  Uses?  Of  what  are 
hair-dyes  and  indelible  inks  made?  Describe  the  process  of 
Daguerreptyping.     Photography. 

173.  Platinum. — Symbol  and  atomic  weight ?  Source?  Prep- 
aration? Properties?  Uses?  How  is  very  fine  platinum  wire 
made? 

174-176.  Mercury. — Symbol  and  atomic  weight?  Common 
name  ?  Why  so  called  ?  Source  ?  Preparation  ?  Properties  ? 
Uses  ?  Action  on  the  human  system  ?  Process  of  silvering 
mirrors?  What  is  blue-pill?  Mercurial  ointment?  Formula  of 
mercuric  oxide  ?  Mercurous  chloride  ?  Mercuric  chloride  ? 
Mercuric  sulphide?    Common  names?    Uses?    Properties? 

The  Alloys. — What  is  an  alloy?  AVhat  peculiarity  with  re- 
gard to  the  melting  point  ?    Of  what  is  type-metal  made  ? 

177. — Pewter?  Britannia?  Brass?  German  silver?  Solder? 
Fusible  metal ?  Bronze?    How  is  gold  soldered ?    Silver?    Copper? 

178. — What  is  the  principle?  What  are  the  constituents  of 
gold  coin?  Silver  coin?  What  is  the  meaning  of  the  term 
carat?    How  are  shot  manufactured?    How  are  they  sorted? 

179-180. — What  is  or-molu?  Aluminium  bronze?  Compare 
the  properties  of  the  metals  with  regard  to,  1,  oxidation;  2, 
density ;  3,  melting  point ;  4,  color ;  5,  malleability  ;  6.  brittle- 
ness ;  7,  tenacity ;  8,  special  properties. 


QUESTIONS     FOR     CLASS     USE.  317 


III.  — ORGANIC     CHEMISTRY. 

185-189.  Introduction. — What  is  organic  chemistry?  What 
was  the  first  organic  substance  artificially  made?  Name  some 
which  have  since  been  made.  What  are  the  organized  bodies? 
What  elements  do  organic  substances  contain?  Explain  the 
great  number  of  organic  substances.  What  is  isomerism?  Are 
organic  molecules  often  complex? 

189-192.  The  Paraffines. — What  is  the  general  formula  of 
this  series  of  hydrocarbons?  Name  some  of  the  members. 
Why  is  the  series  so  called?  Source  of  petroleum?  How  is  it 
pui'ified?  What  are  the  products  of  its  distillation?  Danger  of 
kerosene  explosions.  How  can  the  kerosene  be  tested?  What 
is  paraflSne?  Bitumen?  Its  properties?  Uses?  How  may  the 
paraffines  be  artificially  made? 

193,  194.  The  Alcohols.— What  is  an  alcohol?  Formula  of 
methyl  alcohol?  Its  source?  Its  uses?  Ethyl  alcohol — formula? 
Source  ?    Uses  ?    Effects  on  the  human  system  ? 

195-199.  Fermentation.  —  Cause?  Does  it  ever  take  place 
spontaneously?  How  does  the  yeast  act?  What  change  takes 
place  in  the  alcoholic  fermentation?  The  acetic?  Describe  the 
formation  of  yeast.  The  making  of  malt.  Yeast  cakes.  "What 
is  gluten  ?  How  does  it  act  ?  What  is  diastase  ?  Describe  the 
brewing  of  beer.  Why  is  lager  beer  so  called?  Describe  the 
making  of  wine.  What  is  the  difference  between  a  dry,  a 
sweet,  and  an  effervescing  wine?  Cause  of  the  flavor?  State 
the  proportion  of  alcohol  in  common  liquors.  How  is  brandy 
made? 4  Rum?  Whisky?  Gin?  Describe  the  apparatus  used  for 
distillation.     What  is  fusel  oil? 

200-204.  The  Aldehydes  and  Acids. — What  is  an  alde- 
hyde? Formula  of  ethyl  aldehyde?  How  is  it  formed? 
Formula  of  formic  acid  ?  Occurrence  ?  From  what  is  it 
made?  Formula  of  acetic  acid?  What  is  glacial  acetic  acid? 
How  is  vinegar  made?  What  is  cider  vinegar?  Pyroligne- 
ous  acid?  Properties  of  acetic  acid?  Use?  What  causes 
the  working  of  preserves?  Where  is  oxalic  acid  found?  Prepa- 
ration? Properties?  Antidote?  Uses?  Where  is  malic  acid 
found?     Citric?     Where  is  tartaric  acid   found?     Preparation? 


318  QUESTIONS     FOR     CLASS     USE. 

What  is  cream  of  tartar?  Tartar  emetic?  Rochelle  salt? 
Seidlitz  powders? 

204-209.  The  Ethers  and  Ethereal  Salts. — What  is  an 
ether?  Formula  of  ordinary  ether?  Why  called  "sulphuric" 
ether?  Its  properties?  Uses?  What  are  ethereal  salts?  Illus- 
trate. What  are  the  principal  fats  ?  Formula  of  glycerin  ?  To  what 
class  of  organic  substances  does  it  belong?  From  what  source 
and  how  is  it  obtained?  Properties?  What  is  nitro-glycerin ? 
Dynamite  ?  How  are  candles  made  ?  Illustrate  the  formation  of 
soap.  What  is  the  reaction?  Difference  between  hard  and  soft 
soap?  What  is  the  cause  of  the  curdling  of  soap  in  hard  water? 
Describe   the   cleansing  action  of  soap.     What  is  saponification? 

209,  210.  The  Halogen  Derivatives.  —  Formula  of  chloro- 
form?   How  made?    Properties?    Iodoform?    Chloral? 

211-213.  Starch.  — Formula?  Sources?  Use  in  the  plant? 
Why  stored  in  that  form  ?  Appearance  under  the  microscope  ? 
Preparation?  Properties?  What  is  dextrin?  Test  of  starch? 
Varieties?  What  is  gum?  Composition?  Mucilage?  Is  it 
soluble  in  water?    What  is  pectose?    Pectin? 

213-217.  Cellulose.— Formula?  What  is  the  composition  of 
wood?  Name  the  various  forms  of  cellulin.  Illustrate  the 
wonders  of  secretion.  State  the  uses  of  woody  fiber.  The 
making  of  paper.  Paper-parchment.  Linen.  Cotton.  Gun- 
cotton.     Collodion.    Its  uses. 

217-220.  Sugar. — Cane-sugar?  How  is  sugar  refined?  Dif- 
ference between  loaf  and  granulated  sugar?  Describe  a  centrif- 
ugal machine.  What  is  terra  alba?  Use?  Of  what  are  gum- 
drops  made?  Rock-candy?  What  is  caramel?  Use?  Formula 
of  grape-sugar?  Source?  Sweetening  power?  How  is»  sugar 
made  from  starch?  How  does  the  oil  of  vitriol  act?  How  do 
jellies,  preserves,  etc.,  "candy"?  WTiy  are  dextrose  and  levu- 
lose  so  named?  Why  must  matter  be  organized?  What  is  the 
office  of  plants? 

221-225.  The  Aromatic  Compounds. — Formula  of  benzene? 
Its  source?  Properties?  How  is  nitro-benzene  made?  Its 
formula?  Uses?  Formula  of  aniline?  How  made?  Proper- 
ties? What  is  carbolic  acid?  Picric  acid?  Naphthalene?  An- 
thracene? Benzoic  acid?  Salicylic  acid?  Benzoic  aldehyde? 
Toluene  ? 


QUESTIONS     FOR     CLASS     USE.  319 

225-231.  The  Terpenes  and  Camphors. — How  do  the  volatile 
oils  differ  from  the  fixed  oils?  Sources  of  the  essential  oils? 
Their  preparation?  Their  composition?  Formula  of  oil  of  tur- 
pentine? Its  properties?  What  is  camphene?  Burning  fluid? 
Camphor?  Its  preparation?  Properties?  What  are  the  resins? 
The  balsams?  Illustrate.  What  is  the  source  of  rosin?  Its 
uses?  WTiat  is  lac?.  Difference  between  stick-lac,  seed-lac,  and 
shellac?  How  is  sealing-wax  made?  Source  of  gum-benzoin? 
Uses?  Amber?  Origin?  Properties?  Uses?  India-rubber? 
Source  ?  Properties  ?  Uses  ?  What  is  vulcanized  rubber  ?  Prop- 
erties ?    Gutta-percha  ?    Uses  ? 

231-234.  The  Alkaloids.— Sources?  What  is  opium?  Prep- 
aration? Uses?  Laudanum?  Paregoric?  Danger  of  opium- 
eating?  What  is  morphine?  Use?  Quinine?  Use?  Nicotine? 
Properties?  Strychnine?  Properties?  The  chromatic  test? 
Name  the  active  principle  of  tea  and  coffee.  What  substances 
are  found  in  tea  ?  In  coffee  ?  Describe  the  process  of  tea-raising. 
Of  making  black  tea.     Green  tea. 

235-239.  Dyes  and  Dyeing.  —  Source  of  organic  coloring 
principles?  What  is  an  adjective  color?  A  substantive  color? 
A  mordant  ?  The  process  of  dyeing  ?  Of  cahco  planting  ?  What 
is  madder  ?  Its  coloring  principle  ?  Cochineal  ?  Use  ?  Brazil- 
wood ?  Use  ?  Indigo  ?  Preparation  ?  White  indigo  ?  Logwood  ? 
Litmus  ?  Leaf -green  ?  Tannin  ?  Name  its  varieties.  What  are 
nut-galls  ?  Properties  of  tannin  ?  Describe  the  process  of  tan- 
ning. How  is  leather  blackened?  How  is  ink  made?  Why 
does  writing-fluid  darken  by  exposure  to  the  air?  What  is 
gallic  acid?    Pyi-ogallic  acid?    Use? 

239-243.   Albuminous  Bodies.*  —  What  is  their  composition? 

*  Notice  liere  the  wise  provision  of  nature.  Nitrogen,  slow  and  sluggish 
when  uncombined,  is  fitted  to  dilute  the  air;  while  N,  restless  and  uneasy 
when  combined,  is  equally  adapted  to  form  unstable  compounds  of  food,  to 
carry  force  into  our  bodies  and  there  to  quickly  set  it  free.  Oxygen, 
when  free,  is  active,  eager,  and  ready  to  search  the  nooks  and  crannies  of 
the  capillaries ;  but  when  once  it  combines  with  a  substance,  takes  it  for 
better  or  for  worse,  and  forms  the  stablest  of  compounds.  We  find  nitrogen 
compounds  in  the  animal  and  vegetable  worlds,  ready  for  use  where  they 
are  needed,  in  our  muscles.  Oxygen  compounds  are  abundant  in  the  mineral 
world,  and  stored  in  the  seeds  of  plants,  at  hand  to  give  form  to  the  more 
permanent  parts  of  the  body.     Such  profound  relations,  such  nice  adapta- 


320  QUESTIONS     FOR     CLASS     USE. 

What  is  albumin?  Source?  Properties?  Casein?  Why  does 
milk  curdle  ?  Action  of  rennet  ?  Why  does  cream  rise  on  milk  ? 
Describe  the  souring  of  milk.  Fibrin?  Properties?  Gluten? 
Legumin  ?  Putrefaction  ?  Cause  ?  Why  does  salt  preserve  meat  ? 
What  is  gelatin?    Glue?    Isinglass?    Size? 

243-247.  Domestic  Chemistry.  —  Describe  the  chemical 
changes  which  take  place  in  making  bread.  What  is  stale 
bread  ?  Why  is  it  dry  ?  How  is  aerated  bread  made  ?  Why  is 
bread  ever  sour  ?  How  are  griddle-cakes  raised  ?  Biscuit  ?  What 
are  baking-powders?  Action  of  soda  and  HCl?  Of  sal-volatile? 
How  is  bread  changed  by  toasting?  How  are  potatoes  changed 
by  cooking? 

tions  of  ovir  bodies  to  the  world  around,  give  us  glimpses  of  a  creative  skill 
worthy  of  our  noblest  thought  and  highest  admiration. 


INDEX. 


This  Index  includes  the  Notes  as  well  as  the  Text. 


PAGE 

Acid,  Acetic ^01 

"      Benzoic 224 

"      Boric 120 

"      Carbolic 223 

"     Carbonic 63 

"      Citric 203 

"     Pormic 200 

"     Eulminic 75 

"      Gallic 238 

"  Hydrochloric.  96 
"  Hydrocyanic .  75 
"      Hydrofluoric  .  102 

"     Lactic 240 

"      Malic 203 

"      Muriatic   96 

"     Kitric 30 

"      Oleic 202 

"      Oxalic 203 

"      Palmitic 202 

"     Picric 224 

"     Prussic 75 

"     Pyrogallic 238 

"     Pyroligneous..  201 

"      Salicylic 224 

"      Stearic    202 

"      Sulphuric 105 

"  Sulphurous....  104 
"      Sulphydric. . . .  109 

"■      Tannic 237 

"     Tartaric 203 

Acids 98,  200 

Air 85 

Albumin 239 

Albuminoids,  Veg..  242 

Alcohol,  Amyl 199 

Effects  of.  194 

Ethyl 194 

Methyl....  193 

Alcohols,  The 193 

Aldehyde,  Benzoic.  224 

Ethyl....  200 

Aldehydes,  The 200 


PAGE 

Alizarin 236 

Alkalies 99 

Alkaloids 231 

Alloys 176 

Alum 147 

Alumina 145 

Aluminium 145 

"  Bronze..  179 

"  Silicate.  146 

Amalgam 174 

Amber 229 

Ammonium 136 

Ammonium  Carb. . .  137 

Ammonium  Chlor. .  136 

"  Nitrate  137 

Ammonia 35 

Amyl   Acetate 206 

"       Valerianate.  206 
Anhydride,  Sulph. .  105 

Aniline 222 

Animal  charcoal....     58 

Anthracene 224 

Antimony 176 

Aqua  ammonia 35 

Aqua  f ortis 32 

Aqua  regia 32,  97 

Aromatic  comp'nds  221 

Arsenic 117 

Eating 120 

"       Trioxide....  118 
Arseniuretted     hy- 
drogen    120 

Asphaltum 191 

Asphyxia 66 

Atomic  weight 4 

Atoms 4 

Atmosphere 85 

Atmosphere,      Per- 
manence of 91 

Balsams 227 

Barium 143 


PAGE 

Barium  Chloride.  . .  143 

Bases 99 

Beer 197 

Benzene 221 

Benzine 190 

Benzol 221 

Bessemer's    process 

for  making  steel  155 
Binary  compounds.       6 

Bismuth 177 

Bitumen 191 

Blast-furnace 152 

Bleaching 95 

Bleaching-powder.. .  143 

Blow-pipe 83 

Blow-pipe,     Oxyhy- 

drogen 81 

Bones 242 

Bone-black 58 

Borax 121 

Boron 120 

Brass 177 

Brazil  wood 238 

Bread 243 

Brimstone 103 

Britannia- ware 177 

Bromine 100 

Bronze 177 

Bunsen  burner 81 

Burning-fluid 227 

Butter 206 

Cadmium 144 

Caesium —  137 

Caffeine 234 

Calcimine 139 

Calcium 138 

"       Carbonate..  140 

Chloride....  143 

"       Hydroxide.  139 
"       Hypochlo  - 

rite 143 


322 


INDEX, 


PAGE 

Calcium-Light 

82 

"       Oxide 

138 

"       Phosphate. 

142 

"       Sulphate... 

141 

"       Sulphite. . . 

142 

Calico-printing 

235 

Calomel 

176 

Camphene 

227 

Camphor 

227 

Candles 

207 

Caoutchouc 

229 

Carat 54 

178 

Caramel 

219 

Carbon  

53 

"      Amorphous 

56 

"      Dioxide 

63 

"      Monoxide. . . 

70 

"      Disulphide. 

110 

Carbonic  Acid 

63 

Carburetted  hydro- 

gen  7 

2,  73 

Carmine 

236 

Case-hardening 

154 

Casein 

240 

Cast-iron 

153 

Cells 

214 

Cellulin 

214 

Celluloid 

217 

Cellulose 

213 

Chalk 

140 

Charcoal 

57 

"        Animal  — 

58 

Cheese 

240 

Chemical  Affinity. . . 

o 

Chem.  Harmonica.. 

43 

Chemism 

2 

Chemistry,  Inorg. . . 

7 

Org.... 7 

185 

"         of  candle 

77 

"          "  lamp.. 

79 

"  fire.... 

75 

"        Domestic  243 

Chilled  iron 

153 

Chlorine  . . ; 

92 

Chloroform 

209 

Chlorophyl 

237 

Chloral 

210 

Choke-damp 

67 

Chrome  yellow 

131 

Chromium 

131 

Cinnabar 

174 

Cider 

201 

PAGE 

Classification 6 

Clay 146 

Coal 58 

"    -gas 72 

Cobalt 117 

Cochineal 236 

Coin 178 

Coke 57 

Collodion 217 

Combustion 17,  75 

Compound  ethers...  205 

Compounds 2 

Concrete 139 

Confectionery 218 

Constitution  of  Bod- 
ies    3 

Copper 161 

"      Acetate 161 

"      Carbonate...  161 

"      Oxide 162 

"      Sulphate  ....  162 

Copperas 158 

Coral 140 

Corrosive  sublimate  176 

Cotton 217 

Cream 240 

Cream  of  tartar —  204 

Creosote 193 

Cupellation 168 

Cyanogen 74 

Daguebreottpb 171 

Davy's  Safety  Xiamp    80 
Definite  proportions       3 

Dextrin 212 

Dextrose 219 

Diamond 53 

Diastase 196 

Diffusion,  Law  of..     86 

Disinfectant 95 

Distillation 198 

Drummond  Light. .     82 

Dyeing 235 

Dynamite 207 

EFFLOBE8CEN0K 48 

Elements 1 

"        Table  of...  257 

Equations 5 

Essences 225 

Etching 32,  102 

Ether 205 


PAGE 

Ethereal  Salts 205 

Ethers,  Compound.  205 

"       Mixed 205 

The  204 

Ethyl  Alcohol 194 

"      Butyrate 206 

Fats 206 

Fermentation 195 

Ferrous  Sxilphate...  158 

Fibrin 241 

Fire-damp 71 

Fire-works 130 

Fish,  Breathing  of.     50 

Flame 77 

Fluorine 101 

Formiilas,  Constitu- 
tional   188 

Fulminates 75 

Fusel  on 199 

Fusible  metal 177 

Galena 162 

Galvanized  iron 159 

Gas-carbon 57 

Gas,  Illuminating..     72 
"     Diffusion  of...     86 

"      Olefiant 72 

Gases,"Weighing  and 

measuring 24 

Gelatin 242 

German  silver 177 

Glass 124 

Glazing  of  pottery..  146 

Gluciniun 144 

Gluten 196,  243 

Glue 243 

Glycerin 206 

Gold 165 

Graphite 55 

Gum  Arabic 213 

"      Benzoin 228 

Gun-cotton 217 

Gunpowder 130 

Gutta-percha 231 

Gypsum 141 

Halogens 92 

Hartshorn 35 

Heat 3,17 

Hematite 156 

Hydraulic  lime 139 


INDEX, 


323 


PAGE 

Hydrocarbons 189 

Hydrogen 38 

Hydrogen     sodium 

carbonate 135 

Hydrogen  sulphide.  109 
Hydrogen,      Heav-j' 

carburetted 72 

Hydrogen,    Light 

carbviretted 71 

Hydrogen      p  h  o  s  - 

phide 117 

Igniting-point 17 

India-rubber 229 

Indigo 236 

Ink 238 

"  Printers' 239 

Iodine   101 

Iodoform 210 

Iridium 173 

Iron 150 

Carbonate 157 

Cast   153 

Disulphide 157 

Oxides 156 

Pure 156 

Sulphate 158 

"Wrought 153 

Isomerism 188 

Kerosene 190 


liAC 

Xiampblack 

Laudanum 

Laughing-gas 

Lead 

"    Acetate 

"    Black 

"    Carbonate 

"    Oxides 

"    Red 

"    Sugar  of 

"    Tree 

"    White 

Leather 

Leblanc's  process. . . 

Legumin 

Light 

Lime 

"     Chloride  of.... 

"     Phosphate  of.. 


228 
56 
232 
33 
162 
164 
55 
164 
163 
164 
164 
164 
164 
238 
134 
242 
3 
138 
143 
142 


PAGE 

Lime,  Slaked 139 

"      Superphos- 
phate of . ..  142 

Lime-Light 82 

Limestone 140 

Linen 216 

Lithium 137 

Litmus 237 

Litharge 163 

Logwood 237 

Luminous  paint 117 

Lunar  caustic 170 

Lye 129 

Madder 236 

Magenta 223 

Magnesium 144 

"  Carbon.  145 

Sulph...  145 

Malleable  iron 153 

Malt 196 

Manganese 157 

Marble 140 

Marl 140 

Marsh-gas 71,  189 

Marsh's  test 119 

Matches 114 

Mauve 222 

Mercuric  Oxide 175 

"         Sulphide..  176 

Mercury 174 

"       Chlorides  ..176 

Metals 127 

"      Alkalies 127 

Metals,  Alkaline 

earths....  138 

Noble 165 

"       Properties 

of 179 

Useful 150 

Methyl  Alcohol 193 

Milk 240 

Mirrors 175 

Mixed  gases 40 

Molasses 218 

Molecular  "Weight..       4 

Molecules 4 

Mordants 235 

Morphine 232 

Mortar 139 

Muck 60 

Multiple  proportions    3 


PAGE 

Naphtha 

224 

Naphthalene 

224 

Nascent  state 

37 

177 

Nicotine 

233 

T?9 

Nitric  oxide 

33 

Nitro-Benzene 

222 

"      Glycerin 

207 

"     Toluene 

225 

Nitrous  oxide 

32 

Nitrogen 

27 

Nomenclature 

5 

Nordhausen    sulph. 

acid 

105 

Notation 

5 

Oii,  Bitter  almonds. 

224 

"    Fusel 

199 

' '    Kerosene 

190 

"    Linseed 

238 

"    Turpentine 

226 

"    of  vitriol 

105 

Oils,    "Volatile    and 

essential 

225 

defiant  gas 

72 

Olein 

206 

Opium 

231 

Organic  Chem 7 

,185 

Organizat'n  of  mat- 

220 

Organized  Bodies. . . 

185 

Or-Molu 

179 

Osmium 

173 

Oxygen 

11 

Oxyhydrogen  blow- 

82 

Ozone 

23 

P.ILLADIUM 173 

Palmitin 206 

Paper 215 

Paraffin  e 191 

Paraffin es,  Artiflc'l 

preparation  of..  192 

Paraffines,  The 189 

Parchment 216 

Paregoric 232 

Pearlash 128 

Peat 59 

Pectin 213 

Pencils 56 


324 


INDEX. 


PAOE 

Perciission  caps 75 

Permanence   of   at- 
mosphere      91 

Petrifactions 123 

Petroleum 190 

Pewter 177 

Phenol 223 

Phosphorescence 115 

Phosphorus 113 

Phosphuretted    hy- 
drogen   117 

Photography 171 

Pitch 228 

Plants  in  the  room..     88 
Plants,  Office  of....     90 

Plaster  of  Paris 141 

Platinum 173 

Plumbago 55 

Potash,  Bicarb,  of..  129 
Bitartr'teof  204 

"       Caustic 128 

"       Carbon,  of.  128 
Nitrate  of..  129 

Potassium 127 

Acid  Carb.  129 
Bichrom. .  131 
Carbonate  128 
Chlorate..  131 
Nitrate....  129 

Oxide 128 

Pottery 146 

Prac.  Questions.. 26,  37, 
52, 84, 110, 148, 181, 247 

Preserves 202,  220 

Prussic  acid 75 

Putrefaction 242 

Putty 239 

Pyroxylin 217 

QUARTATION 165 

Quartz 122 

Quicksilver 174 

Quinine 232 

Red  PRECIPITATE 175 

Rennet 240 

Resins 227 

Rhodium 173 

Rochelle  salt 204 

Rosaniline 223 

Rosin 228 


PAOE 

Rubidium 137 

Ruthenium    173 

Sal-ammoniac 136 

Saleratus 129 

Sal-soda 134 

Salt,  Common 132 

"      Epsom 145 

"      Glauber's 134 

"     Rochelle 204 

Salts 99 

Saltpeter 129 

Sal- volatile 137 

Sand 109 

Secretion  214 

SeidUtz  powders 204 

Shellac 228 

Shot 178 

Silicon 122 

SiUca 123 

Silicates 124 

Silver 167 

"     Chloride 172 

"     Nitrate 170 

Smelting 151 

Soap 207 

Soda,  Bicarbon'te  of  135 
"     Carbonate  of..  134 

"     Caustic 134 

Sodium 131 

"       Amalgam..  136 

"       Carbonate..  134 

Chloride....  132 

"       Hydroxide.  134 

"       Nitrate 135 

"       Sulphate 134 

Solar  energy 90 

Solder 177 

Solution 3 

Soot 57 

Spectrum  analysis..  147 
Spongy  platinum.42, 173 
Spontaneoiis     com- 
bustion      18 

Stalactites 140 

Stalagmites 140 

Starch 211,  219 

Stearin 206 

Steel 154 

Strontium 143 

Strychnine 233 


PAGE 

Sucrose 217 

Sugar,  Cane 217 

"       Grape 219 

"       Milk 240 

"       of  lead..  164,  201 

Sulphites 104 

Sulphur 103 

"       Dioxide  ....  104 
"       Trioxide...     105 
Svdphuric  Anhydr..  105 
Sulphuretted  hydro- 
gen   109 

Symbols.. .  5 

Tannin 237 

Tanning 237 

Tartar  emetic 204 

Theine 234 

Tea 234 

Tin 160 

Toluene 225 

Turpentine 226 

Type-metal 176 

Tyrian  purple 236 

Valence 4,  111 

Verdigris 161 

Vermihon 176 

Ventilation 69 

Vinegar 201 

Vitriol,  Blue 162 

"       Green 158 

Oil  of 105 

"       "White 159 

Water 45 

"Water-gas 74 

Wax,  Sealing 228 

^^^lite-lead 164 

"V\Tiite-wash 139 

"Whiting 141 

Wines 197 

Woody  fiber 213 

Yeast 196 

Zinc 158 

"    Chloride 159 

"    Oxide 159 

"   Sulphate 159 

"   White 159 


o 


^.<^ 


GLOSSARY. 


A 

a?'  e  tat^ 

a  9^1'  i-e 

a-e  tin'  ie 

af  fln'ity 

al  biX'min 

al  bu'mi  noias 

al'^l^e  mist      ' 

al'de  hyd^ 

a  liz'a  rin 

al'ka  IT 

al  lo  tr6p'  i-e 

al  loy' 

al  u  mln'i  uni 

a  mar  gain 

am  mo'ni  a 

am  mo  nl'a-e  al 

a  m6r'photis 

am'yl 

an  aes  thet'  i-e 

an  hy'drtd^ 

an  hy'drous 

an'i  Hn^ 

an'thra  pen^ 

an'tl  nno  ny 

a'qua 

Sr  ggn'tum 

Sr'se  ni-e 

Sr  se  ni'  u  rSt  ted 

ar'  ter  y 

as  ph^x'  i  a 


at'om 
a  t6m'i-e 
au'glt^ 

B 

ba'  ri  um 

ba  ry'  te§ 

bSn'zen^ 

ben  zo'i-e 

ben'zol 

ber'yl 

bl  ba'si-e 

bl  -ear-'  bo  nal^ 

bl'na  ry 

bl  nox'id^ 

bl  tu'  men 

bl  tu'  mi  nous 

biv'a  lent 

bo'  rax 

bo'  ri-e 

bo'  ron 

bro'mln^ 

bru'9in^ 

bu'ty  rat^ 

bu  tyr'i-e 

C 

-eae'§i  lim 
■eaf  fe'In^ 
■eaf  fe  o  tan' ni-e 
-eal  ea'  re  otis 
•eal  filled' 


-eal' 91  um 
eal'o  mSl 
eani'  phen^ 
■eaout'chou-e 
(kcJo'chcJok) 
•eap'  il  la  ry 
■ear'  bo  hy  drat^ 
-ear  bol'ie 
-eSr  bo  na'ceotis 
■ear'  bon  at^ 
■eSr  box'  yl 
■ear'  bu  rSt 
ear'  bu  r6t  ted 
ear'  mln^ 
-ea'se  In 
-caus'ti-e 
9^1' lu  lin 
9el'lu  loid 
9el'lu  los^ 
-ehal  9Sd'o  ny 
-eha  lyb'e  at^ 
•el^em'igm 
•eij^Sm'is  try 
■eijlo'ral 
■el^lo'  rin^ 
■eijlo'ro  form 
■el^Io'ro  phyl 
ei^ro  mat' i-e 
■eijrys'  o  pra§^ 
9!n' na  bar 
9lt'  ri^e 


326 


GLOSSARY. 


€6' bait 
•eoch'  i  ne^l 
€ol  lo'di  on 
■edp'per  as 
■ere'o  sot^ 
■eu.  pSr 

■eu  pel  la'tion 
9y'a  nid^ 
gy  an'  o  gen 
9^na'o  gen^ 

D 

de  6x'  i  dlz^ 
dSx'trln 
ddx'  tro§^ 
dl'as  tas^ 
dl6x'Id^ 
dl  stir  phld^ 
d61'o  mlt^ 
dy'  na  mit^ 

E 

6b' on  Tt^ 

e  le€  trol'y  sis 

Sth'yl 

F 

f§r'  ri-e 
fl'brin 
fl'cus 
flu' or  In^ 
mi' ml  nati^ 
ful  mln'i-e 
fu'  sel 

G 

ga  le'  na 
g&l  lo-tan'  ni-e 
gSs'o  11  n^ 
gag  dni'e  ter 
^Sl'atln 


gl6b'ul^ 
glu'ten 
gly9'erln 
graph' it^ 

H 

hal'o  gSn 
ha'loid 
hem' a  tTt^ 
horn'blend^ 
hy  drau'li-e 
hy  dro  bro'  niie 
hy  dro  -ear'bon 
hy  dro  -e^lo'ri-e 
hy  dro  ^y  an'i-e 
hy'dro  gSn 
hy  drSx'yl 
hy  dro  zo'  a 
hy  po  -el^lor'Tl^ 

I 

T'o  did^ 

I'o  dln^ 

T  6d'  o  form 

T  so  mSr'  i-e 

T  s6m'er  i§ni 

I  so  morph'oCis 


jar  go  n61\^' 

K 

kglp 

kSr'o  sen^ 
kl  ndt'  i-e 


la-e 

lau'da  nCim 

le  gu'min 


iT'-el^en 
lith'ardf^ 
lith'i  xim 
lit'  mus 

M 

mag  ne'si  tlm 
mar  a  -eijlt^ 
ma'li-e 
man  ga  ne§V 
mauve  (mov) 
meer'  sJsjhat^m 
mer  -eu'  ri-e 
nier'-eu  roias 
mer'-eu  ry 
mir'  ban^ 
mo  Ig-e'u  lar 
mol'e  -eul^ 
nion  o  ba'  si-e 
mo  nox'id^ 
lYior'dant 
mor'phln^ 
mu  ri  at' i-e 

N 

naph'  tha 
ni-e'o  tin^ 
nl'  trat^ 
nl'  ter 
nl'tri-e 
nl'tro  $en 

O 

o'-ei}.ry 

6€  ta  he'dral 

oe  n&n'  thi-e 

o'le  fi  ant 

6'le  In 

<5'  pi  Hm 


GLOSSARY. 


327 


OP  mo  l\j' 

ox  al'i-e 

ox  i  da'tion 

ox'y  gen 

ox  y  hy'dro  gen 

o'  zon^ 

P 

pal  mlf  i-e 
pal'n-ii  tin 
par'af  fln^ 
p6-e'  tos^ 
pen  t6x'Id^ 
per  man'gan  at^ 
phe'nol 
phe'  nyl 
ph6s'  phin^ 
phos'phu  rSt  ted 
pl'-eri-e 
plat'i  num 
plum  ba'go 
po  tas'si  vim 
pro'te  in 
prtas'  si  at^ 
prtis'  sl-e 
p^  rl'  te§ 
pyr  o  gSl'li-e 
p;y^r  o  llg'  ne  ous 
py  rox'y  11  n 


quad  riv'a  lent 
quer  91  tan'  nie 
qui'  nin^ 
quartz 


R 

rgg'in 

r>alg'o  len^ 

ro§  an'  i  lin^ 

rog'in 

ru  bld'i  tim 


sal-am  mom  ae 

sal  e  ra'tus 

sal  I  9yl'i-e 

sa  p6n  i  fi  -ea'tion 

sar'do  nyx 

s^Id'litz 

sgl'e  nit^ 

ses  qui  €&r'bo  nat^ 

ses  qui  6x'id^ 

shSr  lae 

sT'  lex 

sir  i  -eat^ 

sil'i  -eon 

smalt 

so'di  tim 

s6r'gl;jum 

spath'i-e 

spee'u  lum 

sperm  a  96' tl 

spor'ul^ 

sta  la-e'tlt^ 

sta  lag'  n:ilt^ 

Stan' n  i-e 

Stan' nous 

ste  ar'  i-e 

ste'a  rin 

stom'  a  ta 


str6n'ti  an  it^ 
stron'tl  um 
str^-ei}.'  nln^ 
su'-eros^ 
sul'phur 
sul'phu  r6t  ted 
sulph  y'  dri-e 

T 

tar  tar'  i-e 
ter'  pen^§ 
tet'  a  nus 
the'ln^ 
the  i  tan'ni-e 
tSl'u  en^ 
to  lu'l  d'in^ 
tri  ba'  si-e 
tri  6'  le  at^ 
trI  pal  ml'  tat^ 
tri  ste'a  rat^ 
trlv'a  lent 
tO.r'pen  tln^ 

U 

u  nlv'a  lent 

u'pas 

u'  re  a 

V 

val' en9^ 
ver'dl  gris 
vlt'ri  ol 
vul'-ean  Itfe 


z^f'fer 


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Dana's  Revised  Text-Book  of  Geology 

Edited  by  William  North  Rice,  Ph.D.,  LL.D.,  Professor 
of  Geology,  Wesleyan  University.  Cloth,  i2mo,  482  pages.  $1.40 
This  is  the  standard  text-book  for  high  school  and  elementary 
college  work.  The  book  has  been  thoroughly  revised,  enlarged,  and 
improved,  while  the  general  and  distinctive  features  of  the  former  work 
have  been  preserved.  As  now  published,  it  combines  the  results  of  the 
life  experience  and  observation  of  its  distinguished  author  with  the  latest 
discoveries  and  researches  in  the  science. 

Dana's  Manual  of  Geology 
By  James  D.  Dana. 

Cloth,  8vo,  1087  pages.      1575  illustrations  ....     $5.00 
This  great  work  was  thoroughly  revised  and  entirely  rewritten  under 
the  direct  supervision  of  its  author,  just  before  his  death.     It  is  recog- 
nized as  a  standard  authority,  and  is  used  as  a  manual  of  instruction  in 
all  higher  institutions  of  learning. 

Le  Conte's  Compend  of  Geology 

By  Joseph  Le  Conte,  LL.D.     Cloth,  i2mo,  399  pages      .     $1.20 
Designed  for  high  schools,  academies,  and  all  secondary  schools. 

Steele's  Fourteen  Weeks  in  Geology 

By  J.  Dorman  Steele,  Ph.D.     Cloth,  i2mo,  280  pages     .     $1  00 
A  popular  book  for  elementary  classes  and  the  general  reader. 

Andrews's  Elementary  Geology 

By  E.  B.  Andrews,  LL.D.     Cloth,  i2mo,  283  pages  .     $1.00 

Adapted  for  elementary  classes.     Contains  a  special  treatment  of 

the  geology  of  the  Mississippi  Valley. 


Copies  of  any  of  the  above  books  will  he  sent,  f  repaid,  to  any  address  on 
receipt  of  the  price  by  the  Publishers: 

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Text-Books  in  Astronomy 


Todd's   New  Astronomy 

By  David  P.  Todd,  M.A.,  Ph.D.,  Professor  of  Astronomy 

and  Director  of  the  Observatory,  Amherst  College. 

Cloth,  i2mo,  480  pages.    With  colored  plates  and  illustrations     $1 .30 

A  new  text-book,  designed  for  high  schools,  academies,  and  other 
preparatory  schools.  Its  illuminative  treatment  and  striking  illustra- 
tions make  it  an  ideal  text-book  for  students  and  deeply  interesting 
for  the  general  reader. 

Steele's   New   Descriptive  Astronomy 

By  J.  DoRMAN  Steele,  Ph.D.     Cloth,  i2mo,  338  pages     .     $1.00 

A  popular  text-book,  calculated  to  attract  the  attention  and  awaken 
the  enthusiasm  of  students.  It  supplies  an  adequate  course  in  the  study 
for  high  schools  and  college  preparatory  classes. 

Gillet  and    Rolfe's  Astronomies 

By  J.  A.  GiLLET  and  W.  J.  Rolfe. 

First  Book  in  Astronomy.     Short  Course.     220  pages    .         .     $1.00 

Astronomy.     415  pages         .         .         .         .         .         .         .1.40 

Lockyer's  Astronomies 

By  J.  N.  LocKYER,  F.R.S. 

Astronomy.     (Science  Primer  Series.)     136  pages  .         35  cents 

Elementary  Lessons  in  Astronomy.     312  pages     .         .         .     $1.22 

Bowen's  Astronomy  by  Observation 

By  Eliza  A.  Bowen. 

Boards,  quarto,  94  pages.     Colored  maps  and  illustrations  .     $1.00 

Especially  adapted  for  use  as  an  atlas  to  accompany  any  text-book 
in  astronomy.  Careful  directions  are  given  when,  how,  and  where  to 
find  the  heavenly  bodies. 


Copies  of  any  of  the  above  books  will  be  sent,  prepaid,  to  any  address  on 
receipt  of  the  price  by  the  Publishers: 

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Physiology  and    Hygiene 


Kellogg's  First  Book  in   Physiology  and  Hygiene 

Cloth,  i2mo,  174  pages  .......     40  cents 

Kellogg's  Second  Book  in  Physiology  and  Hygiene 

Cloth,  i2mo,  2qi  pages  .......     80  cents 

These  two  books  constitute  an  entirely  new  and  well  graded  series 
for  the  study  of  Physiology  and  Hygiene  in  schools.  The  subjects  are 
treated  in  a  natural  and  logical  order  and  arranged  in  a  form  suitable  for 
class  instruction.  The  important  subjects  of  sanitation  and  temperance 
are  thoroughly  treated  from  a  scientific  and  physiological  standpoint. 

Smith's  Primer  of  Physiology  and   Hygiene 

Cloth,  i2mo,  174  pages  .......     30  cents 

Smith's  Elementary  Physiology  and   Hygiene 

Cloth,  i2mo,  225  pages  .......     50  cents 

A  complete  and  symmetrical  series  in  which  the  important  facts  of 

Physiology  and  Hygiene  are  presented  in  an  interesting  manner.     The 

Primer  is  designed  for  beginners  in  the  study  and  the  second  book  for 

classes  in  the  intermediate  grades. 

Steele's  Hygienic  Physiology 

Cloth,  1 2mo,  400  pages $1.00 

This  standard  text-book  has  been  thoroughly  revised  and  consider- 
ably enlarged.  It  contains  all  the  excellent  and  popular  features  that 
have  given  Dr.  Steele's  Science  Series  such  wide  use  in  schools  throughout 
the  country. 

The  Same,  abridged.     Cloth,  i2mo,  192  pages      .         .     50  cents 

Tracy's  Essentials  of  Anatomy,  Physiology  and   Hygiene 

Cloth,  i2mo,  345  pages $1.00 

A  practical,  thorough  and  scientific  text-book  of  an  advanced  grade 

for  the  use  of  classes  in  High  Schools,  Academies,  Normal  Schools,  and 

for  private  students. 

Johonnot  and  Bouton's  How  We  Live 

Cloth,  i2mo,  178  pages 40  cents 

An  elementary  text-book  for  beginners  in  which  special  attention  is 

given  to  the  laws  of  Hygiene. 

Walker's  Health  Lessons 

Cloth,  i2mo,  194  pages 48  cents 

A  book  for  beginners,  presenting  the  subjects  in  an  interesting  and 

readable  form  suitable  for  supplementary  readings. 


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receipt  of  the  prire,  by  the  Publishers: 

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Physical   Geography 


Appletons'   Physical   Geography 

By  John  D.  Quackenbos,  John  S.  Newberry,  Charles  H. 
Hitchcock,  W.  Le  Conte  Stevens,  Wm.  H.  Dall,  Henry 
Gannett,  C.  Hart  Merriam,  Nathaniel  L.  Britton, 
George  F.  Kunz  and  Lieut.  Geo.  M.  Stoney. 

Cloth,  quarto,  140  pages  .         .         .         .         .         .         .         $1 .60 

Prepared  on  a  new  and  original  plan.  Richly  illustrated  with  engrav- 
ings, diagrams  and  maps  in  color,  and  including  a  separate  chapter  on 
the  geological  history  and  the  physical  features  of  the  United  States. 
The  aim  has  been  to  popularize  the  study  of  Physical  Geography  by 
furnishing  a  complete,  attractive,  carefully  condensed  text-book. 

Cornell's  Physical  Geography 

Boards,  quarto,  104  pages $1.12 

Revised  edition,  with  such  alterations  and  additions  as  were  found 
necessary  to  bring  the  work  in  all  respects  up  to  date. 

Hinman's   Eclectic   Physical   Geography 

Cloth,  i2mo,  382  pages $1.00 

By  Russell  Hinman.  A  model  text-book  of  the  subject  in  a  new 
and  convenient  form.  It  embodies  a  strictly  scientific  and  accurate 
treatment  of  Physiography  and  other  branches  of  Physical  Geography. 
Adapted  for  classes  in  high  schools,  academies  and  colleges,  and  for 
private  students.  The  text  is  fully  illustrated  by  numerous  maps, 
charts,  cuts  and  diagrams, 

Guyot's  Physical   Geography 

Cloth,  quarto,  124  pages  .......         $1.60 

By  Arnold  Guyot.  Thoroughly  revised  and  supplied  with  newly 
engraved  maps,  illustrations,  etc.  A  standard  work  by  one  of  the  ablest 
of  modern  geographers.  All  parts  of  the  subject  are  presented  in  their 
true  relations  and  in  their  proper  subordination, 

Monteith's   New   Physical   Geography 

Cloth,  quarto,  144  pages  .  .  ,  .  .         .  .  $1.00 

An  elementary  work  adapted  for  use  in  common  and  grammar  schools, 
as  well  as  in  high  schools. 


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receipt  of  the  price ^  by  the  Publishers: 

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Standard   Text-Books  in   Botany 


Clark's  Laboratory  Manual  in   Practical  Botany 

For  Secondary  Schools  and  Elementary  College  work. 

Gray's  How  Plants  Behave         .... 

For  Beginners  in  Primary  Schools. 

Gray's  How  Plants  Grow   ..... 

For  Intermediate  and  Grammar  Schools. 

Gray's  School  and  Field  Book  of  Botany  . 

The  Standard  Te-xt-Hook  for  High  Schools,  Academies,  etc. 
Gray's  Lessons  in  Botany.     (Revised) 
Gray's  Field,  Forest  and  Garden  Botany.     (Flora) 
Gray's  Lessons  and  Manual.     (In  one  volume) 

For  Advanced  Students,  Teachers,  and  Practical  Botanists. 
Gray's  Manual  of  Botany.     (Flora) 

Coulter's  Botany  of  the  Rocky  Mountains 

A  flora  adapted  to  the  mountain  section  of  the  United  States. 

Gray  and  Coulter's  Text-Book  of  Western  Botany 

Being  Gray's  Lessons  and  Coulter's  Manual  bound  in  one  v 
Gray's  Structural   Botany     . 
Goodale's  Physiological  Botany 
Dana's  Plants  and  their  Children 
Merrick's  Chapters  on  Plant  Life 
Steele's  Fourteen  Weeks  in  Botany 
Wood's  How  to  Study  Plants   . 

Same  as  Steele's  Fourteen   Weeks  in  Botany,  with  added  chapters  o 
Physiological  and  Systematic  Botany. 

Wood's  Lessons  in  Botany.     (Revised) 

Wood's  New  American  Botanist  and  Florist.     (Revised) 

Wood's  Descriptive  Botany  .... 

Being  the  flora  of  the  New  American  Botanist  and  Florist. 

Wood's  Class  Book  of  Botany  .... 

A  standard  work  for  Advanced  Classes  and  for  the  Student's  Library 
Youmans's  First  Book  in  Botany 
Youmans's  Descriptive  Botany    . 
Bentley's  Physiological  Botany  . 

A  sequel  to  Youmans's  Descriptive  Botany, 

Willis's  Practical  Flora 

A  valuable  supplementary  aid  to  any  text-book  in  the  study  of  Botany. 


$0.96 

54 

.80 

1.80 

.94 
1.44 
2.16 

1.62 
1.62 

2  16 

2.00 
2.00 
.65 
.60 
1.00 
1.00 

.90 
1.75 
1  25 

2.50 

.64 
1.20 
1.20 

1.50 


Copies  of  any  of  the  above  books  will  be  sent,  f  repaid,  to  any  address  on 
receipt  of  t lie  price  by  the  Publishers: 


NEW  YORK 

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